WO2019078205A1 - Substrate equipped with multi-layer reflection film, reflection-type mask blank, reflection-type mask, and semiconductor device manufacturing process - Google Patents

Substrate equipped with multi-layer reflection film, reflection-type mask blank, reflection-type mask, and semiconductor device manufacturing process Download PDF

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Publication number
WO2019078205A1
WO2019078205A1 PCT/JP2018/038499 JP2018038499W WO2019078205A1 WO 2019078205 A1 WO2019078205 A1 WO 2019078205A1 JP 2018038499 W JP2018038499 W JP 2018038499W WO 2019078205 A1 WO2019078205 A1 WO 2019078205A1
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Prior art keywords
film
multilayer reflective
reflective film
reference mark
substrate
Prior art date
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PCT/JP2018/038499
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French (fr)
Japanese (ja)
Inventor
和宏 浜本
笑喜　勉
洋平 池邊
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Hoya株式会社
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Application filed by Hoya株式会社 filed Critical Hoya株式会社
Priority to SG11202002424RA priority Critical patent/SG11202002424RA/en
Priority to US16/754,306 priority patent/US11281090B2/en
Priority to KR1020207006753A priority patent/KR102724034B1/en
Priority to JP2019549294A priority patent/JP7168573B2/en
Publication of WO2019078205A1 publication Critical patent/WO2019078205A1/en

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/22—Masks or mask blanks for imaging by radiation of 100nm or shorter wavelength, e.g. X-ray masks, extreme ultraviolet [EUV] masks; Preparation thereof
    • G03F1/24—Reflection masks; Preparation thereof
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/38—Masks having auxiliary features, e.g. special coatings or marks for alignment or testing; Preparation thereof
    • G03F1/44—Testing or measuring features, e.g. grid patterns, focus monitors, sawtooth scales or notched scales
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/22—Masks or mask blanks for imaging by radiation of 100nm or shorter wavelength, e.g. X-ray masks, extreme ultraviolet [EUV] masks; Preparation thereof
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/38—Masks having auxiliary features, e.g. special coatings or marks for alignment or testing; Preparation thereof
    • G03F1/42—Alignment or registration features, e.g. alignment marks on the mask substrates
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/38—Masks having auxiliary features, e.g. special coatings or marks for alignment or testing; Preparation thereof
    • G03F1/48—Protective coatings
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/54—Absorbers, e.g. of opaque materials
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/68—Preparation processes not covered by groups G03F1/20 - G03F1/50
    • G03F1/82—Auxiliary processes, e.g. cleaning or inspecting
    • G03F1/84—Inspecting
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/20—Exposure; Apparatus therefor

Definitions

  • the present invention relates to a multilayer reflective film coated substrate, a reflective mask blank, a reflective mask, and a method of manufacturing a semiconductor device.
  • EUV lithography which is an exposure technique using Extreme Ultra Violet (hereinafter referred to as EUV) light
  • EUV light refers to light in the wavelength band of the soft X-ray region or the vacuum ultraviolet region, and specifically, light having a wavelength of about 0.2 to 100 nm.
  • a reflective mask has been proposed as a mask used in EUV lithography. In the reflective mask, a multilayer reflective film that reflects exposure light is formed on a substrate such as glass or silicon, and an absorber film pattern that absorbs the exposure light is formed on the multilayer reflective film.
  • a reflective mask mounted thereon In an exposure machine that performs pattern transfer, light incident on a reflective mask mounted thereon is absorbed at a portion having an absorber film pattern and is reflected by the multilayer reflective film at a portion having no absorber film pattern. Then, the reflected light image is transferred onto a semiconductor substrate such as a silicon wafer via a reflection optical system.
  • One of the problems is a problem regarding defect information of a mask blank substrate or the like used in the lithography process.
  • the position of the defect of the substrate is specified by the distance from the origin by using the substrate center as the origin (0, 0) and using the coordinates managed by the defect inspection apparatus. For this reason, the reference of the absolute value coordinate is not clear, the position accuracy is low, and the detection varies among the devices. Further, even when patterning is performed on a thin film for pattern formation avoiding a defect when drawing a pattern, it is difficult to avoid the defect in the order of ⁇ m. For this reason, the defect is avoided by changing the direction in which the pattern is transferred, or roughly shifting the transfer position in the order of mm.
  • Patent Document 1 discloses a fiducial mark formed in a concave shape by removing a part of the multilayer reflective film.
  • a method of removing a part of the multilayer reflective film a laser ablation method or FIB (focused ion beam method) is disclosed.
  • the multilayer reflective film may be etched in the depth direction.
  • the material of the multilayer reflective film for example, a Mo / Si film may be exposed on the side surface of the recess formed by the etching.
  • the Mo film may be exposed to the surface.
  • etching reactant may adhere to the side or bottom.
  • the process of manufacturing the reflective mask blank or the reflective mask includes the process of cleaning the substrate.
  • the present invention can prevent the surface of the multilayer reflective film from being contaminated even when the reference mark is formed on the multilayer reflective film, a substrate with a multilayer reflective film, a reflective mask blank, a reflective mask,
  • An object of the present invention is to provide a method of manufacturing a semiconductor device.
  • Another object of the present invention is to provide a substrate with a multilayer reflective film, a reflective mask blank, a reflective mask, and a method of manufacturing a semiconductor device, which can prevent deterioration in the cleaning resistance of the substrate.
  • Another object of the present invention is to provide a method of manufacturing a substrate with a multilayer reflective film, a reflective mask blank, a reflective mask, and a semiconductor device capable of shortening the time required for processing a reference mark.
  • the present invention has the following composition.
  • (Configuration 1) A multilayer reflective film coated substrate comprising: a substrate; a multilayer reflective film for reflecting EUV light formed on the substrate; and a protective film formed on the multilayer reflective film, It has a fiducial mark formed concavely on the surface of the protective film, The surface layer of the reference mark contains an element identical to at least one of the elements contained in the protective film, A multilayer reflective film coated substrate having a shrink region in which at least a part of a plurality of films included in the multilayer reflective film is contracted at the bottom of the reference mark.
  • (Configuration 7) A reflective mask blank having a multilayer reflective film coated substrate according to any one of constitutions 1 to 6 and an absorber film for absorbing EUV light formed on a protective film of the multilayer reflective film coated substrate. There, A reflective mask blank, wherein the shape of the reference mark is transferred to the absorber film.
  • Configuration 9 A method of manufacturing a semiconductor device, comprising the step of forming a transfer pattern on a semiconductor substrate using the reflective mask according to Configuration 8.
  • the multilayer reflective film coated substrate, the reflective mask blank, the reflective mask, and the like can prevent the surface of the multilayer reflective film from being contaminated. And a method of manufacturing a semiconductor device.
  • a multilayer reflective film coated substrate, a reflective mask blank, a reflective mask, and a method of manufacturing a semiconductor device which can prevent the deterioration of the cleaning resistance of the substrate.
  • FIG. 3 is a cross-sectional view of the reference mark shown in FIG. 2 along the line BB.
  • FIG. 1 shows a pattern transfer device. It is a TEM image of the cross section of a fiducial mark.
  • FIG. 1 is a schematic view showing a cross section of the multilayer reflective film coated substrate of this embodiment.
  • the multilayer reflective film coated substrate 10 includes a substrate 12, a multilayer reflective film 14 that reflects EUV light that is exposure light, and a protective film 18 for protecting the multilayer reflective film 14.
  • a multilayer reflective film 14 is formed on the substrate 12, and a protective film 18 is formed on the multilayer reflective film 14.
  • the substrate or film includes not only the case of contacting the upper surface of the substrate or film, but also the case of not contacting the upper surface of the substrate or film. That is, “on” the substrate or film includes the case where a new film is formed above the substrate or film, the case where another film is interposed between the substrate or film, etc. . Moreover, “on” does not necessarily mean the upper side in the vertical direction, but merely indicates the relative positional relationship of the substrate, the film, and the like.
  • the substrate 12 used for the multilayer reflective film coated substrate 10 of the present embodiment has a low thermal conductivity within the range of 0 ⁇ 5 ppb / ° C. to prevent distortion of the absorber film pattern due to heat during exposure.
  • Those having an expansion coefficient are preferably used.
  • As a material having a low thermal expansion coefficient in this range for example, SiO 2 —TiO 2 based glass, multicomponent glass ceramics, etc. can be used.
  • the main surface on the side where the transfer pattern of the substrate 12 (the absorber film pattern described later corresponds thereto) is preferably processed to enhance the flatness.
  • the flatness is preferably 0.1 ⁇ m or less, more preferably 0.05 ⁇ m or less, in a 132 mm ⁇ 132 mm region of the main surface of the substrate 12 on the side where the transfer pattern is formed.
  • it is 0.03 micrometer or less.
  • the main surface opposite to the side on which the transfer pattern is formed is the surface fixed to the exposure apparatus by the electrostatic chuck, and the flatness is 1 ⁇ m or less, more preferably 0 in the 142 mm ⁇ 142 mm region. 0.5 ⁇ m or less, particularly preferably 0.03 ⁇ m or less.
  • flatness is a value representing surface warpage (amount of deformation) indicated by TIR (Total Indicated Reading), and a plane determined by the least squares method with respect to the substrate surface is taken as a focal plane, It is the absolute value of the height difference between the highest position of the substrate surface above the plane and the lowest position of the substrate surface below the focal plane.
  • the surface roughness of the main surface on the side where the transfer pattern of the substrate 12 is formed is preferably 0.1 nm or less in root mean square roughness (RMS).
  • the surface roughness can be measured by an atomic force microscope.
  • the substrate 12 preferably has high rigidity in order to prevent deformation due to film stress of a film (such as the multilayer reflective film 14) formed thereon.
  • the substrate 12 preferably has a high Young's modulus of 65 GPa or more.
  • the multilayer reflective film coated substrate 10 includes a substrate 12 and a multilayer reflective film 14 formed on the substrate 12.
  • the multilayer reflective film 14 is, for example, a multilayer film in which elements having different refractive indexes are periodically stacked.
  • the multilayer reflective film 14 has a function of reflecting EUV light.
  • the multilayer reflective film 14 is a thin film (high refractive index layer) of a light element or its compound which is a high refractive index material, and a thin film (a low refractive index layer) of a heavy element or its compound which is a low refractive index material And the like are alternately laminated in about 40 to 60 cycles.
  • a high refractive index layer and a low refractive index layer may be laminated in a plurality of cycles in this order from the substrate 12 side. In this case, the laminated structure of one (high refractive index layer / low refractive index layer) is one cycle.
  • a low refractive index layer and a high refractive index layer may be laminated in a plurality of cycles in this order from the substrate 12 side.
  • the laminated structure of one (low refractive index layer / high refractive index layer) is one cycle.
  • the uppermost layer of the multilayer reflective film 14, that is, the surface layer of the multilayer reflective film 14 opposite to the substrate 12 is preferably a high refractive index layer.
  • the uppermost layer is the low refractive index layer.
  • the low refractive index layer is the surface of the multilayer reflective film 14
  • the low refractive index layer is easily oxidized to reduce the reflectance of the multilayer reflective film, so that the low refractive index layer is formed on the low refractive index layer. Form a high refractive index layer.
  • the uppermost layer is the high refractive index layer.
  • the uppermost high refractive index layer is the surface of the multilayer reflective film 14.
  • the high refractive index layer may be a layer containing Si.
  • the high refractive index layer may contain Si alone or may contain a Si compound.
  • the Si compound may contain Si and at least one element selected from the group consisting of B, C, N, and O.
  • the low refractive index material at least one element selected from the group consisting of Mo, Ru, Rh and Pt, or at least one selected from the group consisting of Mo, Ru, Rh and Pt Alloys containing one element can be used.
  • the multilayer reflective film 14 for EUV light with a wavelength of 13 to 14 nm preferably, a Mo / Si multilayer film in which Mo films and Si films are alternately stacked for about 40 to 60 cycles can be used.
  • a multilayer reflective film used in the region of EUV light for example, Ru / Si periodic multilayer film, Mo / Be periodic multilayer film, Mo compound / Si compound periodic multilayer film, Si / Nb periodic multilayer film, Si / A Mo / Ru periodic multilayer film, a Si / Mo / Ru / Mo periodic multilayer film, a Si / Ru / Mo / Ru periodic multilayer film or the like can be used.
  • the material of the multilayer reflective film can be selected in consideration of the exposure wavelength.
  • the reflectivity of such a multilayer reflective film 14 alone is, for example, 65% or more.
  • the upper limit of the reflectance of the multilayer reflective film 14 is, for example, 73%.
  • the thickness and period of the layers included in the multilayer reflective film 14 can be selected so as to satisfy Bragg's law.
  • the multilayer reflective film 14 can be formed by a known method.
  • the multilayer reflective film 14 can be formed, for example, by ion beam sputtering.
  • the multilayer reflective film 14 is a Mo / Si multilayer film
  • a Mo film having a thickness of about 3 nm is formed on the substrate 12 using an Mo target by ion beam sputtering.
  • a Si target is used to form a Si film having a thickness of about 4 nm.
  • the surface layer opposite to the substrate 12 of the multilayer reflective film 14 is a layer containing Si (Si film).
  • the thickness of one cycle of Mo / Si film is 7 nm.
  • the multilayer reflective film coated substrate 10 of the present embodiment is provided with a protective film 18 formed on the multilayer reflective film 14.
  • the protective film 18 has a function of protecting the multilayer reflective film 14 in patterning or pattern correction of the absorber film.
  • the protective film 18 is provided between the multilayer reflective film 14 and an absorber film described later.
  • the protective film 18 As a material of the protective film 18, for example, Ru, Ru- (Nb, Zr, Y, B, Ti, La, Mo, Co or Re) compound, Si- (Ru, Rh, Cr or B) compound, Si, Materials such as Zr, Nb, La, B and the like can be used. Moreover, the compound which added nitrogen, oxygen, or carbon to these can be used. Among these, when a material containing ruthenium (Ru) is applied, the reflectance characteristics of the multilayer reflective film become better. Specifically, the material of the protective film 18 is preferably Ru or Ru- (Nb, Zr, Y, B, Ti, La, Mo, Co or Re) compound. The thickness of the protective film 18 is, for example, 1 nm to 5 nm. The protective film 18 can be formed by a known method. The protective film 18 can be formed by, for example, a magnetron sputtering method or an ion beam sputtering method.
  • the multilayer reflective film coated substrate 10 may further have a back surface conductive film on the main surface of the substrate 12 opposite to the side on which the multilayer reflective film 14 is formed.
  • the back surface conductive film is used when adsorbing the multilayer reflective film coated substrate 10 or the reflective mask blank by an electrostatic chuck.
  • the multilayer reflective film coated substrate 10 may have a base film formed between the substrate 12 and the multilayer reflective film 14.
  • the underlayer is formed, for example, for the purpose of improving the smoothness of the surface of the substrate 12.
  • the undercoat film is formed, for example, for the purpose of defect reduction, improvement of the reflectance of the multilayer reflective film, and stress correction of the multilayer reflective film.
  • FIG. 2 is a plan view of the multilayer reflective film coated substrate 10 of the present embodiment.
  • reference marks 20 which can be used as a reference of the defect position in the defect information are respectively formed.
  • the number of reference marks 20 is not limited to four, and may be three or less, or five or more.
  • the region inside the broken line A (a region of 132 mm ⁇ 132 mm) is a pattern formation region in which an absorber film pattern is formed when the reflective mask is manufactured.
  • the area outside the broken line A is an area where the absorber film pattern is not formed when the reflective mask is manufactured.
  • the reference mark 20 is preferably formed in the area where the absorber film pattern is not formed, that is, the area outside the broken line A.
  • the reference mark 20 has a substantially cruciform shape.
  • the width W of one line of the reference mark 20 having a substantially cruciform shape is, for example, 200 nm or more and 10 ⁇ m or less.
  • the length L of one line of the reference mark 20 is, for example, not less than 100 ⁇ m and not more than 1500 ⁇ m.
  • FIG. 2 shows an example of the reference mark 20 having a substantially cross shape, the shape of the reference mark 20 is not limited to this.
  • the shape of the reference mark 20 may be, for example, a substantially L-shape in plan view.
  • FIG. 3 is a cross-sectional view taken along the line BB of the reference mark 20 shown in FIG. 2, and schematically shows the cross-sectional structure of the reference mark 20.
  • a reference mark when looking at a cross section of the multilayer reflective film coated substrate 10 (cross section perpendicular to the main surface of the multilayer reflective film coated substrate 10). 20 are formed in a concave shape on the surface of the protective film 18.
  • the term "concave” as used herein means that when the cross section of the multilayer reflective film coated substrate 10 is viewed, the reference mark 20 is formed to be recessed, for example, in a step-like shape or in a curved shape downward from the protective film 18 It is a meaning.
  • the surface layer 22 of the reference mark 20 contains the same element as at least one of the elements contained in the protective film 18.
  • the surface layer 22 of the reference mark 20 contains at least one element selected from the group consisting of Ru, Nb, Zr, Y, B, Ti, La, Mo, Co, Re, Si, Rh, and Cr. It is done.
  • the surface layer 22 of the reference mark 20 preferably contains ruthenium (Ru) which is the same element as the element contained in the protective film 18.
  • the types of elements contained in the surface layer 22 of the reference mark 20 can be identified by, for example, EDX (energy dispersive X-ray analysis).
  • the surface layer 22 of the reference mark 20 may contain an oxide of the same element as at least one of the elements contained in the protective film 18.
  • the surface layer 22 of the reference mark 20 may be Ru, Ru- (Nb, Zr, Y, B, Ti, La, Mo, Co or Re) compound, Si- (Ru, Rh, Cr or B) compound, Si
  • An oxide of at least one element or compound selected from the group consisting of Zr, Nb, La, and B may be included.
  • the surface layer 22 of the reference mark 20 may contain an oxide of Ru or RuNb.
  • the surface layer 22 of the reference mark 20 may include at least one of RuO and RuNbO.
  • the “surface layer 22” of the reference mark 20 means, for example, a region from the surface of the reference mark 20 to a depth of 2 nm.
  • the surface layer 22 contains the same element as the element contained in the protective film 18.
  • the same element as the element contained in the protective film 18 may be contained in the entire surface of the surface layer 22 or may be contained in a part of the surface layer 22.
  • the same element as the element contained in the protective film 18 is contained in the entire surface layer 22. In this case, the material contained in the multilayer reflective film 14 is not exposed, and the cleaning resistance of the multilayer reflective film coated substrate 10 can be prevented from being deteriorated.
  • the surface layer 14 a of the multilayer reflective film 14 on the opposite side to the substrate 12 is preferably a layer containing Si (Si film). This is because Ru and Si react with each other in the surface layer 22 of the reference mark 20 to form RuSi by heat when the reference mark 20 is laser-processed, so that the cleaning resistance of the multilayer reflective film coated substrate 10 is improved.
  • the surface layer 22 of the reference mark 20 contains, for example, at least one of RuSi and RuSiO. May be
  • a shrink region 24 in which at least a part of the plurality of films included in the multilayer reflective film 14 is contracted is formed.
  • the bottom of the reference mark 20 means an area below the concave surface layer 22 up to the top surface of the substrate 12.
  • the thickness of at least a part of the plurality of films included in the multilayer reflective film 14 is shrunk.
  • the multilayer reflective film 14 is a Mo / Si multilayer film in which a 3 nm thick Mo film and a 4 nm thick Si film are periodically stacked
  • the thickness of one cycle Mo / Si film is 7 nm. is there.
  • the thickness of one cycle of the Mo / Si film shrinks from 7 nm to 6 nm.
  • the contraction ratio of the thickness of the multilayer reflective film 14 is about 86%.
  • the contraction rate of the thickness of the multilayer reflective film 14 is preferably 75% to 95%, and more preferably 80% to 90%.
  • the shrink region 24 at least a part of the plurality of films included in the multilayer reflective film 14 is shrunk, but the multilayer structure of the multilayer reflective film 14 is maintained. That the laminated structure of the multilayer reflective film 14 is maintained can be easily confirmed, for example, by a TEM image of a cross section of the multilayer reflective film-attached substrate 10.
  • At least a part of the plurality of films included in the multilayer reflective film 14 is integrated with each other in the vicinity of the central portion of the bottom of the reference mark 20 and above the shrink region 24.
  • a mixing area 26 is formed.
  • a plurality of films included in the multilayer reflective film 14 react with each other by heat generated when the reference mark 20 is laser-processed and integrated.
  • the multilayer reflective film 14 is a Mo / Si multilayer film
  • the Mo film and the Si film react with each other in the mixing region 26 to generate MoSi.
  • the mixing area 26 is likely to be formed near the central part of the bottom of the reference mark 20, but may be formed in parts other than the central part. 200 nm or less is preferable and, as for the thickness of the mixing area
  • the thickness of the mixing area 26 mentioned here means the maximum value of the thickness in the vertical direction of the mixing area 26.
  • FIG. 3 shows an example in which the mixing area 26 is formed, the mixing area 26 may not be formed depending on the conditions of the laser processing and the like.
  • the multilayer structure of the multilayer reflective film 14 is not maintained.
  • the integration of the plurality of films included in the multilayer reflective film 14 can be easily confirmed by, for example, a TEM image of a cross section of the multilayer reflective film-coated substrate 10.
  • the depth D of the concave reference mark 20 is preferably 30 nm or more and 50 nm.
  • the depth D means the vertical distance from the surface of the protective film 18 to the deepest position at the bottom of the reference mark 20.
  • the inclination angle ⁇ of the concave reference mark 20 is preferably less than 25 degrees, and more preferably 3 degrees or more and 10 degrees or less.
  • the inclination angle ⁇ means the angle between the extension line 22 a of the surface layer 22 of the reference mark 20 and the surface 18 a of the protective film 18 when the cross section of the reference mark 20 is viewed.
  • the method of forming the reference mark 20 is not particularly limited.
  • the reference mark 20 can be formed, for example, by laser processing on the surface of the protective film 18.
  • the conditions for laser processing are, for example, as follows.
  • Laser power 1 to 120 mW Scanning speed: 0.1 to 20 mm / s
  • Pulse frequency 1 to 100 MHz
  • Pulse width 3ns to 1000s
  • the laser used for laser processing the reference mark 20 may be a continuous wave or a pulse wave.
  • the width W of the reference mark 20 can be made smaller than that of the continuous wave, even if the depth D of the reference mark 20 is approximately the same.
  • the inclination angle ⁇ of the reference mark 20 can be made larger than that of a continuous wave. Therefore, when the pulse wave is used, it is possible to form the reference mark 20 which has a larger contrast than the continuous wave and is easy to detect by the defect inspection apparatus or the electron beam drawing apparatus.
  • the fiducial mark 20 can be used, for example, as an FM (fiducial mark).
  • the FM is a mark used as a reference of defect coordinates when drawing a pattern by the electron beam drawing apparatus.
  • the FM is usually in the shape of a cross as shown in FIG.
  • the reference mark 20 is formed on the multilayer reflective film coated substrate 10
  • the coordinates of the reference mark 20 and the coordinates of the defect are acquired with high accuracy by the defect inspection apparatus.
  • an absorber film is formed on the protective film 18 of the multilayer reflective film coated substrate 10.
  • a resist film is formed on the absorber film.
  • a hard mask film (or an etching mask film) may be formed between the absorber film and the resist film.
  • the concave reference mark 20 formed on the protective film 18 of the multilayer reflective film coated substrate 10 is transferred to an absorber film and a resist film, or transferred to an absorber film, a hard mask film and a resist film. Ru.
  • the reference mark 20 transferred to the resist film is used as the FM which is the reference of the defect position.
  • the reference marks 20 formed on the multilayer reflective film coated substrate 10 need to have high contrast that is detectable by the defect inspection apparatus.
  • a defect inspection apparatus for example, a mask substrate / blank defect inspection apparatus “MAGICSM 7360” for EUV exposure manufactured by Lasertec having an inspection light source wavelength of 266 nm, an EUV manufactured by KLA-Tencor having an inspection light source wavelength of 193 nm
  • Mask / blank defect inspection apparatus “Teron 600 series, for example, Teron 610” there is an ABI (Actinic Blank Inspection) apparatus whose inspection light source wavelength is the same as 13.5 nm of exposure light source wavelength.
  • the reference mark 20 transferred to the absorber film and the resist film thereon needs to have a contrast high enough to be detected by the electron beam drawing apparatus. Furthermore, it is preferable that the reference mark 20 have a contrast high enough to be detected by the coordinate measuring device.
  • the coordinate measuring device can convert the coordinates of the defect acquired by the defect inspection device into reference coordinates of the electron beam drawing device. Therefore, the user provided with the multilayer reflective film coated substrate 10 can easily and precisely match the defect position identified by the defect inspection apparatus with the drawing data based on the reference mark 20.
  • defect coordinates can be managed with high accuracy.
  • the defect coordinates can be converted to the coordinate system of the electron beam drawing apparatus by detecting the FM by the electron beam drawing apparatus. Then, for example, the drawing data of the pattern drawn by the electron beam drawing apparatus can be corrected such that the defect is disposed below the absorber film pattern. This can reduce the influence of defects on the reflective mask finally manufactured (this method is called a defect mitigation process).
  • the fiducial mark 20 can also be used as an AM (alignment mark).
  • AM is a mark that can be used as a reference of the defect coordinates when the defect inspection apparatus inspects a defect on the multilayer reflective film 14.
  • AM is not directly used when drawing a pattern by an electron beam drawing apparatus.
  • AM can be in the shape of a circle, a square, a cross, or the like.
  • AM When AM is formed on the multilayer reflective film 14, it is preferable to form FM on the absorber film on the multilayer reflective film 14 and to partially remove the absorber film on the AM.
  • AM can be detected by a defect inspection apparatus and a coordinate measuring instrument.
  • the FM can be detected by a coordinate measuring instrument and an electron beam drawing apparatus.
  • FIG. 4 is a schematic view showing a cross section of the reflective mask blank 30 of the present embodiment.
  • the reflective mask blank 30 of this embodiment can be manufactured by forming the absorber film 28 that absorbs EUV light on the protective film 18 of the multilayer reflective film coated substrate 10 described above.
  • the absorber film 28 has a function of absorbing EUV light which is exposure light. That is, the difference between the reflectance of the multilayer reflective film 14 to EUV light and the reflectance of the absorber film 28 to EUV light is equal to or greater than a predetermined value. For example, the reflectance of the absorber film 28 to EUV light is 0.1% or more and 40% or less. There may be a predetermined phase difference between the light reflected by the multilayer reflective film 14 and the light reflected by the absorber film 28. In this case, the absorber film 28 in the reflective mask blank 30 may be called a phase shift film.
  • the absorber film 28 preferably has a function of absorbing EUV light and can be removed by etching or the like.
  • the absorber film 28 is preferably etchable by dry etching using a chlorine (Cl) -based gas or a fluorine (F) -based gas.
  • the material of the absorber film 28 is not particularly limited as long as the absorber film 28 has such a function.
  • the absorber film 28 may be a single layer or may have a laminated structure.
  • a plurality of films made of the same material may be laminated, or a plurality of films made of different materials may be laminated.
  • the material and the composition may change stepwise and / or continuously in the thickness direction of the film.
  • the material of the absorber film 28 is preferably, for example, tantalum (Ta) alone or a material containing Ta.
  • the material containing Ta is, for example, a material containing Ta and B, a material containing Ta and N, a material containing Ta and B, and at least one of O and N, a material containing Ta and Si, Ta and Si A material containing N, a material containing Ta and Ge, a material containing Ta, Ge and N, a material containing Ta and Pd, a material containing Ta and Ru, a material containing Ta and Ti, etc.
  • the absorber film 28 includes, for example, a single Ni, a material containing Ni, a single Cr, a material containing Cr, a single Ru, a material containing Ru, a single Pd, a material containing Pd, a single Mo, and a material containing Mo. And at least one selected from the group consisting of
  • the thickness of the absorber film 28 is preferably 30 nm to 100 nm.
  • the absorber film 28 can be formed by a known method, for example, a magnetron sputtering method, an ion beam sputtering method, or the like.
  • the resist film 32 may be formed on the absorber film 28. This aspect is shown in FIG. After a pattern is drawn and exposed on the resist film 32 by an electron beam drawing apparatus, a resist pattern can be formed through a development process. By performing dry etching on the absorber film 28 using this resist pattern as a mask, a pattern can be formed on the absorber film 28.
  • the resist film 32 above the reference mark 20 may be locally removed so that the concave reference mark 20 formed on the protective film 18 can be easily detected by the electron beam lithography system.
  • the mode of removal is not particularly limited. Also, for example, the resist film 32 and the absorber film 28 above the reference mark 20 may be removed.
  • a hard mask film may be formed between the absorber film 28 and the resist film 32.
  • the hard mask film is used as a mask when patterning the absorber film 28.
  • the hard mask film and the absorber film 28 are formed of materials having different etching selectivity.
  • the material of the absorber film 28 contains tantalum or a tantalum compound
  • the material of the hard mask film preferably contains chromium or a chromium compound.
  • the chromium compound preferably contains at least one selected from the group consisting of Cr and N, O, C, and H.
  • the reflective mask blank 30 of the present embodiment can be used to manufacture the reflective mask 40 of the present embodiment.
  • a method of manufacturing the reflective mask 40 will be described.
  • FIG. 5 is a schematic view showing a method of manufacturing the reflective mask 40.
  • the substrate 12, the multilayer reflective film 14 formed on the substrate 12, the protective film 18 formed on the multilayer reflective film 14, and the protective film 18 are formed.
  • a reflective mask blank 30 having the absorber film 28 is prepared (FIG. 5A).
  • a resist film 32 is formed on the absorber film 28 (FIG. 5B).
  • a pattern is drawn on the resist film 32 by an electron beam drawing apparatus, and a resist pattern 32a is formed by passing through a developing and rinsing process (FIG. 5C).
  • the absorber film 28 is dry etched using the resist pattern 32a as a mask. As a result, the portion of the absorber film 28 not covered by the resist pattern 32a is etched to form the absorber film pattern 28a (FIG. 5 (d)).
  • etching gas for example, chlorine based gases such as Cl 2 , SiCl 4 , CHCl 3 and CCl 4 , mixed gas containing these chlorine based gases and O 2 in a predetermined ratio, chlorine based gases and He as predetermined.
  • chlorine based gases such as Cl 2 , SiCl 4 , CHCl 3 and CCl 4
  • mixed gas containing these chlorine based gases and O 2 in a predetermined ratio chlorine based gases and He as predetermined.
  • the resist pattern 32a is removed by, for example, a resist remover.
  • the reflective mask 40 of the present embodiment is obtained by passing through a wet cleaning process using an acidic or alkaline aqueous solution (FIG. 5E).
  • a transfer pattern can be formed on a semiconductor substrate by lithography using the reflective mask 40 of the present embodiment.
  • the transfer pattern has a shape in which the absorber film pattern 28 a of the reflective mask 40 is transferred.
  • a semiconductor device can be manufactured by forming a transfer pattern on the semiconductor substrate using the reflective mask 40.
  • FIG. 6 shows a pattern transfer device 50.
  • the pattern transfer apparatus 50 includes a laser plasma X-ray source 52, a reflective mask 40, a reduction optical system 54, and the like.
  • As the reduction optical system 54 an X-ray reflection mirror is used.
  • the pattern reflected by the reflective mask 40 is usually reduced to about 1 ⁇ 4 by the reduction optical system 54.
  • a wavelength band of 13 to 14 nm is used as an exposure wavelength, and the light path is set in advance so as to be in vacuum.
  • EUV light generated by the laser plasma X-ray source 52 is made incident on the reflective mask 40.
  • the light reflected by the reflective mask 40 is transferred onto the resisted semiconductor substrate 56 via the reduction optical system 54.
  • the light incident on the reflective mask 40 is absorbed by the absorber film and not reflected at a portion where the absorber film pattern 28 a is present. On the other hand, the light incident on the portion without the absorber film pattern 28 a is reflected by the multilayer reflective film 14.
  • the light reflected by the reflective mask 40 enters the reduction optical system 54.
  • the light incident on the reduction optical system 54 forms a transfer pattern on the resist layer on the semiconductor substrate with resist 56.
  • a resist pattern can be formed on the resist-coated semiconductor substrate 56.
  • etching the semiconductor substrate 56 using the resist pattern as a mask for example, a predetermined wiring pattern can be formed on the semiconductor substrate.
  • a semiconductor device is manufactured through such steps and other necessary steps.
  • the reference mark 20 is formed in a concave shape on the surface of the protective film 18.
  • the surface layer of the reference mark 20 contains an element identical to at least one element among the elements contained in the protective film 18.
  • a shrink region 24 is formed in which at least a part of the plurality of films included in the multilayer reflective film 14 is contracted.
  • the multilayer reflective film coated substrate 10 of the present embodiment it is possible to prevent the surface of the multilayer reflective film 14 from being contaminated by dust generated during laser processing of the reference mark 20. It is considered that at least a part of the protective film 18 remains on the surface layer 22 of the reference mark 20.
  • the multilayer reflective film coated substrate 10 of the present embodiment it is possible to prevent the material of the multilayer reflective film 14 from being exposed on the surface of the reference mark 20. Therefore, the multilayer reflective film coated substrate 10, the reflective mask blank 30, and the reflective mask 40 having excellent cleaning resistance can be manufactured.
  • the multilayer reflective film coated substrate 10 of the present embodiment it is possible to shorten the time required to process the reference mark as compared to the case of using the FIB method.
  • Example 1 A SiO 2 -TiO 2 based glass substrate (6 inches square, 6.35 mm thick) was prepared. The end face of this glass substrate was chamfered and ground, and was roughly polished with a polishing solution containing cerium oxide abrasive grains. The glass substrate after these treatments was set on the carrier of the double-side polishing apparatus, and precision polishing was performed under predetermined polishing conditions using an alkaline aqueous solution containing colloidal silica abrasive grains as the polishing solution. After completion of the precision polishing, the glass substrate was subjected to a cleaning treatment.
  • the surface roughness of the main surface of the obtained glass substrate was 0.10 nm or less in root mean square roughness (RMS).
  • the flatness of the main surface of the obtained glass substrate was 30 nm or less in a measurement area of 132 mm ⁇ 132 mm.
  • a multilayer reflective film was formed by periodically laminating an Mo film / Si film on the main surface of the glass substrate opposite to the side on which the back surface conductive film was formed.
  • an Mo target and a Si target were used, and an Mo film and a Si film were alternately stacked on the substrate by ion beam sputtering (using Ar).
  • the thickness of the Mo film is 2.8 nm.
  • the thickness of the Si film is 4.2 nm.
  • the thickness of one cycle of Mo / Si film is 7.0 nm.
  • Such a Mo / Si film was laminated 40 cycles, and finally, a Si film was formed to a thickness of 4.0 nm to form a multilayer reflective film.
  • a protective film containing a Ru compound was formed on the multilayer reflective film. Specifically, a RuNb target (Ru: 80 at%, Nb: 20 at%) is used, and a protective film made of RuNb is formed on the multilayer reflective film by DC magnetron sputtering in an Ar gas atmosphere. did. The thickness of the protective film was 2.5 nm.
  • a reference mark was formed on the protective film by laser processing.
  • the conditions for laser processing were as follows.
  • Laser type Semiconductor laser with a wavelength of 405 nm
  • Laser output 20 mW (continuous wave)
  • Spot size 430 nm ⁇
  • the shape and dimensions of the fiducial marks were as follows. Shape: approximately cruciform depth D: 40 nm Width W: 2 ⁇ m Length L: 1 mm Inclination angle ⁇ : 5.7 degrees
  • FIG. 7 An image obtained by photographing is shown in FIG.
  • a shrink region in which at least a part of the plurality of films included in the multilayer reflective film is shrunk is formed.
  • a mixing region in which at least a part of the plurality of films included in the multilayer reflective film are integrated.
  • the thickness of one cycle of Mo / Si film included in the multilayer reflective film decreased from 7.0 nm to 6.0 nm.
  • the thickness of the mixing area was 120 nm.
  • the surface of the fiducial marks was analyzed by EDX (energy dispersive x-ray analysis).
  • the surface layer of the shrink region of the reference mark contained Ru and Nb which are the same elements as the elements contained in the protective film.
  • oxygen (O) was also detected, it is considered that RuNbO is contained in the surface layer of the reference mark.
  • Ru, Nb, Si, Mo and O were contained in the surface layer of the mixing area of the reference mark, it is considered that RuNbO, RuSi, MoSi or the like is contained.
  • Defect inspection of the multilayer reflective film coated substrate was performed using a defect inspection apparatus (ABI manufactured by Lasertec Corporation).
  • defect inspection the position of a defect was specified on the basis of a fiducial mark formed concavely on the protective film. As a result, the number of defects was reduced compared to the case where the fiducial marks were formed by the conventional FIB method.
  • An absorber film was formed on the protective film of the multilayer reflective film coated substrate to manufacture a reflective mask blank. Specifically, an absorber film made of a laminated film of TaBN (56 nm in thickness) and TaBO (14 nm in thickness) was formed by DC magnetron sputtering.
  • the TaBN film was formed by reactive sputtering in a mixed gas atmosphere of Ar gas and N 2 gas using a TaB target.
  • the TaBO film was formed by reactive sputtering in a mixed gas atmosphere of Ar gas and O 2 gas using a TaB target.
  • the concave reference mark transferred to the absorber film was detected by an electron beam writing apparatus. As a result, it was possible to detect that the reference mark was detectable, and it was possible to confirm that the reference mark transferred to the absorber film had a contrast sufficient to be detectable by the electron beam lithography system.
  • Defect inspection on the absorber film was performed using a defect inspection apparatus (M8350 manufactured by Lasertec Corporation).
  • the position of the defect was specified on the basis of the fiducial mark transferred concavely on the absorber film.
  • the number of defects was reduced compared to the case where the fiducial marks were formed by the conventional FIB method.
  • a resist film was formed on the absorber film of the reflective mask blank manufactured above.
  • a pattern was drawn on a resist film based on defect information obtained by defect inspection using an electron beam drawing apparatus. After drawing the pattern, predetermined development processing was performed to form a resist pattern on the absorber film.
  • the resist pattern as a mask, a pattern was formed on the absorber film. Specifically, the upper TaBO film was dry etched with a fluorine-based gas (CF 4 gas), and then the lower TaBN film was dry etched with a chlorine-based gas (Cl 2 gas).
  • CF 4 gas fluorine-based gas
  • Cl 2 gas chlorine-based gas
  • the reflective mask according to Example 1 was obtained by removing the resist pattern remaining on the absorber film pattern with hot sulfuric acid.
  • good pattern transfer can be performed without defects in the transfer pattern caused by the reflective mask. it can.
  • Example 2 A SiO 2 -TiO 2 based glass substrate (6 inches square, 6.35 mm thick) was prepared. The end face of this glass substrate was chamfered and ground, and was roughly polished with a polishing solution containing cerium oxide abrasive grains. The glass substrate after these treatments was set on the carrier of the double-side polishing apparatus, and precision polishing was performed under predetermined polishing conditions using an alkaline aqueous solution containing colloidal silica abrasive grains as the polishing solution. After completion of the precision polishing, the glass substrate was subjected to a cleaning treatment. The surface roughness of the main surface of the obtained glass substrate was 0.10 nm or less in root mean square roughness (RMS). The flatness of the main surface of the obtained glass substrate was 30 nm or less in a measurement area of 132 mm ⁇ 132 mm.
  • RMS root mean square roughness
  • a multilayer reflective film was formed by periodically laminating an Mo film / Si film on the main surface of the glass substrate opposite to the side on which the back surface conductive film was formed.
  • an Mo target and a Si target were used, and an Mo film and a Si film were alternately stacked on the substrate by ion beam sputtering (using Ar).
  • the thickness of the Mo film is 2.8 nm.
  • the thickness of the Si film is 4.2 nm.
  • the thickness of one cycle of Mo / Si film is 7.0 nm.
  • Such a Mo / Si film was laminated 40 cycles, and finally, a Si film was formed to a thickness of 4.0 nm to form a multilayer reflective film.
  • a protective film containing Ru was formed on the multilayer reflective film. Specifically, a Ru target was used, and a protective film made of a Ru film was formed on the multilayer reflective film by DC magnetron sputtering in an Ar gas atmosphere. The thickness of the protective film was 2.5 nm.
  • a reference mark was formed on the protective film by laser processing.
  • the conditions for laser processing were as follows.
  • Laser type Semiconductor laser with a wavelength of 405 nm
  • Laser output 20 mW (continuous wave)
  • Spot size 430 nm ⁇
  • the shape and dimensions of the fiducial marks were as follows. Shape: approximately cruciform depth D: 40 nm Width W: 2 ⁇ m Length L: 1 mm Inclination angle ⁇ : 5.7 degrees
  • the surface of the fiducial marks was analyzed by EDX (energy dispersive x-ray analysis).
  • EDX energy dispersive x-ray analysis
  • the surface layer of the shrink region of the reference mark contained Ru, which is the same element as the element contained in the protective film.
  • oxygen (O) was also detected, it is considered that RuO is contained in the surface layer of the reference mark.
  • Ru, Si, Mo, and O were contained in the surface layer of the mixing area
  • Defect inspection of the multilayer reflective film coated substrate was performed using a defect inspection apparatus (ABI manufactured by Lasertec Corporation).
  • defect inspection the position of a defect was specified on the basis of a fiducial mark formed concavely on the protective film. As a result, the number of defects was reduced compared to the case where the fiducial marks were formed by the conventional FIB method.
  • An absorber film was formed on the protective film of the multilayer reflective film coated substrate to manufacture a reflective mask blank. Specifically, an absorber film made of a laminated film of TaBN (56 nm in thickness) and TaBO (14 nm in thickness) was formed by DC magnetron sputtering.
  • the TaBN film was formed by reactive sputtering in a mixed gas atmosphere of Ar gas and N 2 gas using a TaB target.
  • the TaBO film was formed by reactive sputtering in a mixed gas atmosphere of Ar gas and O 2 gas using a TaB target.
  • the concave reference mark transferred to the absorber film was detected by an electron beam writing apparatus. As a result, it was possible to detect that the reference mark was detectable, and it was possible to confirm that the reference mark transferred to the absorber film had a contrast sufficient to be detectable by the electron beam lithography system.
  • Defect inspection on the absorber film was performed using a defect inspection apparatus (M8350 manufactured by Lasertec Corporation).
  • the position of the defect was specified on the basis of the fiducial mark transferred concavely on the absorber film.
  • the number of defects was reduced compared to the case where the fiducial marks were formed by the conventional FIB.
  • a resist film was formed on the absorber film of the reflective mask blank manufactured above.
  • a pattern was drawn on a resist film based on defect information obtained by defect inspection using an electron beam drawing apparatus. After drawing the pattern, predetermined development processing was performed to form a resist pattern on the absorber film.
  • the resist pattern as a mask, a pattern was formed on the absorber film. Specifically, the upper TaBO film was dry etched with a fluorine-based gas (CF 4 gas), and then the lower TaBN film was dry etched with a chlorine-based gas (Cl 2 gas).
  • CF 4 gas fluorine-based gas
  • Cl 2 gas chlorine-based gas
  • the resist pattern remaining on the absorber film pattern was removed with hot sulfuric acid to obtain a reflective mask according to Example 2.
  • a reflective mask according to Example 2.
  • Example 3 A SiO 2 -TiO 2 based glass substrate (6 inches square, 6.35 mm thick) was prepared. The end face of this glass substrate was chamfered and ground, and was roughly polished with a polishing solution containing cerium oxide abrasive grains. The glass substrate after these treatments was set on the carrier of the double-side polishing apparatus, and precision polishing was performed under predetermined polishing conditions using an alkaline aqueous solution containing colloidal silica abrasive grains as the polishing solution. After completion of the precision polishing, the glass substrate was subjected to a cleaning treatment. The surface roughness of the main surface of the obtained glass substrate was 0.10 nm or less in root mean square roughness (RMS). The flatness of the main surface of the obtained glass substrate was 30 nm or less in a measurement area of 132 mm ⁇ 132 mm.
  • RMS root mean square roughness
  • a multilayer reflective film was formed by periodically laminating an Mo film / Si film on the main surface of the glass substrate opposite to the side on which the back surface conductive film was formed.
  • an Mo target and a Si target were used, and an Mo film and a Si film were alternately stacked on the substrate by ion beam sputtering (using Ar).
  • the thickness of the Mo film is 2.8 nm.
  • the thickness of the Si film is 4.2 nm.
  • the thickness of one cycle of Mo / Si film is 7.0 nm.
  • Such a Mo / Si film was laminated 40 cycles, and finally, a Si film was formed to a thickness of 4.0 nm to form a multilayer reflective film.
  • a protective film containing a Ru compound was formed on the multilayer reflective film. Specifically, a RuNb target (Ru: 80 at%, Nb: 20 at%) is used, and a protective film made of RuNb is formed on the multilayer reflective film by DC magnetron sputtering in an Ar gas atmosphere. did. The thickness of the protective film was 2.5 nm.
  • a reference mark was formed on the protective film by laser processing.
  • the conditions for laser processing were as follows.
  • Laser type Semiconductor laser with a wavelength of 405 nm
  • Laser output 10 mW (continuous wave)
  • Spot size 430 nm ⁇
  • the shape and dimensions of the fiducial marks were as follows. Shape: approximately cruciform depth D: 38 nm Width W: 2 ⁇ m Length L: 1 mm Inclination angle ⁇ : 3.6 degrees
  • the surface of the fiducial marks was analyzed by EDX (energy dispersive x-ray analysis).
  • EDX energy dispersive x-ray analysis
  • the surface layer of the reference mark contained Ru and Nb, which are the same elements as the elements contained in the protective film.
  • Defect inspection of the multilayer reflective film coated substrate was performed using a defect inspection apparatus (ABI manufactured by Lasertec Corporation).
  • defect inspection the position of a defect was specified on the basis of a fiducial mark formed concavely on the protective film. As a result, the number of defects was reduced compared to the case where the fiducial marks were formed by the conventional FIB method.
  • An absorber film was formed on the protective film of the multilayer reflective film coated substrate to manufacture a reflective mask blank. Specifically, an absorber film made of a laminated film of TaBN (56 nm in thickness) and TaBO (14 nm in thickness) was formed by DC magnetron sputtering.
  • the TaBN film was formed by reactive sputtering in a mixed gas atmosphere of Ar gas and N 2 gas using a TaB target.
  • the TaBO film was formed by reactive sputtering in a mixed gas atmosphere of Ar gas and O 2 gas using a TaB target.
  • the concave reference mark transferred to the absorber film was detected by an electron beam writing apparatus. As a result, it was possible to detect that the reference mark was detectable, and it was possible to confirm that the reference mark transferred to the absorber film had a contrast sufficient to be detectable by the electron beam lithography system.
  • Defect inspection on the absorber film was performed using a defect inspection apparatus (M8350 manufactured by Lasertec Corporation).
  • the position of the defect was specified on the basis of the fiducial mark transferred concavely on the absorber film.
  • the number of defects was reduced compared to the case where the fiducial marks were formed by the conventional FIB method.
  • a resist film was formed on the absorber film of the reflective mask blank manufactured above.
  • a pattern was drawn on a resist film based on defect information obtained by defect inspection using an electron beam drawing apparatus. After drawing the pattern, predetermined development processing was performed to form a resist pattern on the absorber film.
  • the resist pattern as a mask, a pattern was formed on the absorber film. Specifically, the upper TaBO film was dry etched with a fluorine-based gas (CF 4 gas), and then the lower TaBN film was dry etched with a chlorine-based gas (Cl 2 gas).
  • CF 4 gas fluorine-based gas
  • Cl 2 gas chlorine-based gas
  • the resist pattern remaining on the absorber film pattern was removed with hot sulfuric acid to obtain a reflective mask according to Example 3.
  • a reflective mask according to Example 3.
  • a SiO 2 -TiO 2 based glass substrate (6 inches square, 6.35 mm thick) was prepared. The end face of this glass substrate was chamfered and ground, and was roughly polished with a polishing solution containing cerium oxide abrasive grains.
  • the glass substrate after these treatments was set on the carrier of the double-side polishing apparatus, and precision polishing was performed under predetermined polishing conditions using an alkaline aqueous solution containing colloidal silica abrasive grains as the polishing solution. After completion of the precision polishing, the glass substrate was subjected to a cleaning treatment.
  • the surface roughness of the main surface of the obtained glass substrate was 0.10 nm or less in root mean square roughness (RMS).
  • the flatness of the main surface of the obtained glass substrate was 30 nm or less in a measurement area of 132 mm ⁇ 132 mm.
  • a multilayer reflective film was formed by periodically laminating an Mo film / Si film on the main surface of the glass substrate opposite to the side on which the back surface conductive film was formed.
  • an Mo target and a Si target were used, and an Mo film and a Si film were alternately stacked on the substrate by ion beam sputtering (using Ar).
  • the thickness of the Mo film is 2.8 nm.
  • the thickness of the Si film is 4.2 nm.
  • the thickness of one cycle of Mo / Si film is 7.0 nm.
  • Such a Mo / Si film was laminated 40 cycles, and finally, a Si film was formed to a thickness of 4.0 nm to form a multilayer reflective film.
  • a protective film containing a Ru compound was formed on the multilayer reflective film. Specifically, a RuNb target (Ru: 80 at%, Nb: 20 at%) is used, and a protective film made of RuNb is formed on the multilayer reflective film by DC magnetron sputtering in an Ar gas atmosphere. did. The thickness of the protective film was 2.5 nm.
  • a fiducial mark was formed on the protective film by FIB.
  • the conditions of FIB were as follows. Acceleration voltage: 50kV Beam current value: 20 pA
  • the shape and dimensions of the fiducial marks were as follows. Shape: approximately cruciform depth D: 40 nm Width W: 2 ⁇ m Length L: 1 mm Inclination angle ⁇ : 86 degrees
  • the surface of the fiducial marks was analyzed by EDX (energy dispersive x-ray analysis).
  • EDX energy dispersive x-ray analysis
  • the surface layer of the reference mark did not contain Ru and Nb, which are the same elements as the elements contained in the protective film, and Mo and Si were detected. Since no protective film remains on the surface layer of the reference mark, it is considered that the material of the multilayer reflective film was exposed.
  • Defect inspection of the multilayer reflective film coated substrate was performed using a defect inspection apparatus (ABI manufactured by Lasertec Corporation).
  • defect inspection the position of a defect was specified on the basis of a fiducial mark formed concavely on the protective film.
  • the number of defects was significantly increased as compared with Examples 1 to 3. It is presumed that the surface of the multilayer reflective film is contaminated by dust generated when the fiducial mark is processed by FIB.
  • the time to process the fiducial marks was significantly increased as compared with Examples 1 to 3.
  • An absorber film was formed on the protective film of the multilayer reflective film coated substrate to manufacture a reflective mask blank. Specifically, an absorber film made of a laminated film of TaBN (56 nm in thickness) and TaBO (14 nm in thickness) was formed by DC magnetron sputtering.
  • the TaBN film was formed by reactive sputtering in a mixed gas atmosphere of Ar gas and N 2 gas using a TaB target.
  • the TaBO film was formed by reactive sputtering in a mixed gas atmosphere of Ar gas and O 2 gas using a TaB target.
  • Defect inspection on the absorber film was performed using a defect inspection apparatus (M8350 manufactured by Lasertec Corporation).
  • the position of the defect was specified on the basis of the fiducial mark transferred concavely on the absorber film.
  • the number of defects was significantly increased as compared with Examples 1 to 3.
  • a resist film was formed on the absorber film of the reflective mask blank manufactured above.
  • a pattern was drawn on a resist film based on defect information obtained by defect inspection using an electron beam drawing apparatus. After drawing the pattern, predetermined development processing was performed to form a resist pattern on the absorber film.
  • the resist pattern as a mask, a pattern was formed on the absorber film. Specifically, the upper TaBO film was dry etched with a fluorine-based gas (CF 4 gas), and then the lower TaBN film was dry etched with a chlorine-based gas (Cl 2 gas).
  • CF 4 gas fluorine-based gas
  • Cl 2 gas chlorine-based gas
  • a reflective mask according to Comparative Example 1 was obtained.
  • the number of defects in the transfer pattern caused by the reflective mask is greater than in the first to third embodiments. It is difficult to perform good pattern transfer.

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Abstract

Provided are: a multi-layer reflection film-equipped substrate that is capable of preventing contamination of the surface of the multi-layer reflection film even when a reference mark is formed on the multi-layer reflection film; a reflection-type mask blank; a reflection-type mask; and a semiconductor device manufacturing process. This multi-layer reflection film-equipped substrate 10 comprises: a substrate 12; a multi-layer reflection film 14 which is formed on the substrate 12 so as to be capable of reflecting EUV light; and a protective film 18 formed on the multi-layer reflection film 14. The protective film 18 has an indented reference mark 20 formed in the surface thereof. At least one of the chemical elements contained in the protective film 18 is identical to an element contained in a superficial layer 22 of the reference mark 20. The reference mark 20 has, at a bottom section thereof, a shrink region 24 that is formed as a result of the shrinking of at least one of the multiple films included in the multi-layer reflection film 14.

Description

多層反射膜付き基板、反射型マスクブランク、反射型マスク、及び半導体装置の製造方法Multilayer reflective film coated substrate, reflective mask blank, reflective mask, and method of manufacturing semiconductor device
　本発明は、多層反射膜付き基板、反射型マスクブランク、反射型マスク、及び半導体装置の製造方法に関する。 The present invention relates to a multilayer reflective film coated substrate, a reflective mask blank, a reflective mask, and a method of manufacturing a semiconductor device.
　近年における超ＬＳＩデバイスの高密度化、高精度化の更なる要求に伴い、極紫外（Extreme Ultra Violet、以下、ＥＵＶと称す）光を用いた露光技術であるＥＵＶリソグラフィーが有望視されている。ここで、ＥＵＶ光とは、軟Ｘ線領域又は真空紫外線領域の波長帯の光を指し、具体的には波長が０．２～１００ｎｍ程度の光のことである。ＥＵＶリソグラフィーにおいて用いられるマスクとして、反射型マスクが提案されている。反射型マスクは、ガラスやシリコンなどの基板上に、露光光を反射する多層反射膜が形成され、その多層反射膜の上に露光光を吸収する吸収体膜パターンが形成されたものである。パターン転写を行う露光機において、それに搭載された反射型マスクに入射した光は、吸収体膜パターンのある部分では吸収され、吸収体膜パターンのない部分では多層反射膜により反射される。そして反射された光像が、反射光学系を介してシリコンウエハ等の半導体基板上に転写される。 With the further demand for higher density and higher accuracy of ultra LSI devices in recent years, EUV lithography, which is an exposure technique using Extreme Ultra Violet (hereinafter referred to as EUV) light, is considered promising. Here, EUV light refers to light in the wavelength band of the soft X-ray region or the vacuum ultraviolet region, and specifically, light having a wavelength of about 0.2 to 100 nm. A reflective mask has been proposed as a mask used in EUV lithography. In the reflective mask, a multilayer reflective film that reflects exposure light is formed on a substrate such as glass or silicon, and an absorber film pattern that absorbs the exposure light is formed on the multilayer reflective film. In an exposure machine that performs pattern transfer, light incident on a reflective mask mounted thereon is absorbed at a portion having an absorber film pattern and is reflected by the multilayer reflective film at a portion having no absorber film pattern. Then, the reflected light image is transferred onto a semiconductor substrate such as a silicon wafer via a reflection optical system.
　リソグラフィー工程での微細化に対する要求が高まることにより、リソグラフィー工程における課題が顕著になりつつある。その課題の１つが、リソグラフィー工程で用いられるマスクブランク用基板等の欠陥情報に関する問題である。 With the increasing demand for miniaturization in the lithography process, the problems in the lithography process are becoming more pronounced. One of the problems is a problem regarding defect information of a mask blank substrate or the like used in the lithography process.
  従来は、ブランクス検査等において、基板の欠陥の存在位置を、基板センターを原点（０，０）とし、欠陥検査装置が管理する座標を用いて、その原点からの距離で特定していた。このため、絶対値座標の基準が明確でなく、位置精度が低く、装置間でも検出のばらつきがあった。また、パターン描画時に、欠陥を避けてパターン形成用薄膜にパターニングする場合でも、μｍオーダーでの欠陥の回避は困難であった。このため、パターンを転写する方向を変えたり、転写する位置をｍｍオーダーでラフにずらしたりして、欠陥を回避していた。 Conventionally, in a blank inspection or the like, the position of the defect of the substrate is specified by the distance from the origin by using the substrate center as the origin (0, 0) and using the coordinates managed by the defect inspection apparatus. For this reason, the reference of the absolute value coordinate is not clear, the position accuracy is low, and the detection varies among the devices. Further, even when patterning is performed on a thin film for pattern formation avoiding a defect when drawing a pattern, it is difficult to avoid the defect in the order of μm. For this reason, the defect is avoided by changing the direction in which the pattern is transferred, or roughly shifting the transfer position in the order of mm.
　このような状況下、例えばマスクブランク用基板に基準マークを形成し、基準マークを基準として欠陥の位置を特定することが提案されている。マスクブランク用基板に基準マークを形成することにより、装置毎に欠陥の位置を特定するための基準がずれることが防止される。 Under such circumstances, for example, it has been proposed to form a reference mark on a mask blank substrate and to specify the position of a defect with reference to the reference mark. By forming the reference marks on the mask blank substrate, it is possible to prevent deviation of the reference for specifying the position of the defect for each device.
　露光光としてＥＵＶ光を使用する反射型マスクにおいては、多層反射膜上の欠陥の位置を正確に特定することが特に重要である。なぜなら、多層反射膜に存在する欠陥は、修正がほとんど不可能である上に、転写パターン上で重大な位相欠陥となり得るためである。 In a reflective mask that uses EUV light as exposure light, it is particularly important to pinpoint the location of defects on the multilayer reflective film. The reason is that the defects present in the multilayer reflective film are almost impossible to correct and may become serious phase defects on the transfer pattern.
　多層反射膜上の欠陥の位置を正確に特定するためには、多層反射膜を形成した後に欠陥検査を行うことで、欠陥の位置情報を取得することが好ましい。そのためには、基板に形成された多層反射膜に、基準マークを形成することが好ましい。 In order to pinpoint the position of the defect on a multilayer reflective film correctly, it is preferable to acquire the positional information on a defect by performing defect inspection after forming a multilayer reflective film. For that purpose, it is preferable to form a reference mark on the multilayer reflective film formed on the substrate.
　特許文献１には、多層反射膜の一部を除去することで凹状に形成された基準マークが開示されている。多層反射膜の一部を除去する方法としては、レーザアブレーション法やＦＩＢ（集束イオンビーム法）が開示されている。 Patent Document 1 discloses a fiducial mark formed in a concave shape by removing a part of the multilayer reflective film. As a method of removing a part of the multilayer reflective film, a laser ablation method or FIB (focused ion beam method) is disclosed.
国際公開ＷＯ２０１３／０３１８６３号International Publication WO 2013/031863
　しかしながら、多層反射膜の表面にレーザアブレーション法によって凹状の基準マークを形成した場合、レーザ加工時に発生した塵によって、多層反射膜の表面が汚染されることがある。多層反射膜の表面が汚染された場合、新たな異物欠陥が生じることがある。新たな異物欠陥が生じた場合、それが露光欠陥となる欠陥であれば、反射型マスクを作製したときに重大な問題が生じることがある。 However, when a concave reference mark is formed on the surface of the multilayer reflective film by laser ablation, dust generated during laser processing may contaminate the surface of the multilayer reflective film. If the surface of the multilayer reflective film is contaminated, new foreign matter defects may occur. When a new foreign matter defect occurs, if it is a defect that becomes an exposure defect, serious problems may occur when producing a reflective mask.
　多層反射膜に凹状の基準マークを形成するために、多層反射膜を深さ方向にエッチングすることがある。多層反射膜を深さ方向にエッチングした場合、エッチングによって生じた凹部の側面では、多層反射膜の材料である、例えばＭｏ／Ｓｉ膜が露出する場合がある。エッチングによって生じた凹部の底部では、Ｍｏ膜が表面に露出する場合がある。また、エッチング反応物が側面や底部に付着することもある。多層反射膜に含まれる材料が露出した場合、基板の洗浄耐性が悪化する。反射型マスクブランクあるいは反射型マスクの製造工程には、基板の洗浄工程が含まれている。基板の洗浄耐性が悪化した場合、基板の洗浄工程において、基準マークの側面及び／又は底部の材料が溶出し、マーク形状の変動、エッジラフネスの増加などの位置精度の悪化、エッチング面からの膜剥がれ等の問題が生じることがある。また、付着物は、洗浄工程により、剥がれ、再付着の汚染リスクがある。 In order to form a concave reference mark in the multilayer reflective film, the multilayer reflective film may be etched in the depth direction. When the multilayer reflective film is etched in the depth direction, the material of the multilayer reflective film, for example, a Mo / Si film may be exposed on the side surface of the recess formed by the etching. At the bottom of the recess formed by etching, the Mo film may be exposed to the surface. In addition, etching reactant may adhere to the side or bottom. When the material contained in the multilayer reflective film is exposed, the cleaning resistance of the substrate is deteriorated. The process of manufacturing the reflective mask blank or the reflective mask includes the process of cleaning the substrate. When the cleaning resistance of the substrate is deteriorated, the material of the side and / or bottom of the reference mark is eluted in the cleaning step of the substrate, the mark shape fluctuates, the positional accuracy is deteriorated such as an increase in edge roughness, and the film from the etching surface Problems such as peeling may occur. In addition, there is a risk of contamination due to peeling off and re-deposition due to the cleaning process.
　多層反射膜の表面にＦＩＢ法によって凹状の基準マークを形成する場合には、ＦＩＢ法の加工速度は遅いために、加工に要する時間が長くなる。このため、要求される長さ（例えば550μm）の基準マークを作製することが困難となる。 In the case of forming a concave reference mark on the surface of the multilayer reflective film by the FIB method, the processing speed of the FIB method is slow, so the time required for processing becomes long. This makes it difficult to produce a reference mark of the required length (for example, 550 μm).
　そこで、本発明は、多層反射膜に基準マークを形成した場合でも、多層反射膜の表面が汚染されることを防止することのできる、多層反射膜付き基板、反射型マスクブランク、反射型マスク、及び半導体装置の製造方法を提供することを目的とする。また、基板の洗浄耐性が悪化することを防止することのできる、多層反射膜付き基板、反射型マスクブランク、反射型マスク、及び半導体装置の製造方法を提供することを目的とする。さらに、基準マークの加工に要する時間を短くすることのできる、多層反射膜付き基板、反射型マスクブランク、反射型マスク、及び半導体装置の製造方法を提供することを目的とする。 Therefore, the present invention can prevent the surface of the multilayer reflective film from being contaminated even when the reference mark is formed on the multilayer reflective film, a substrate with a multilayer reflective film, a reflective mask blank, a reflective mask, An object of the present invention is to provide a method of manufacturing a semiconductor device. Another object of the present invention is to provide a substrate with a multilayer reflective film, a reflective mask blank, a reflective mask, and a method of manufacturing a semiconductor device, which can prevent deterioration in the cleaning resistance of the substrate. Another object of the present invention is to provide a method of manufacturing a substrate with a multilayer reflective film, a reflective mask blank, a reflective mask, and a semiconductor device capable of shortening the time required for processing a reference mark.
　上記課題を解決するため、本発明は以下の構成を有する。
（構成１）
　基板と、前記基板上に形成されたＥＵＶ光を反射する多層反射膜と、前記多層反射膜上に形成された保護膜とを含む多層反射膜付き基板であって、
　前記保護膜の表面に凹状に形成された基準マークを備え、
　前記基準マークの表層は、前記保護膜に含まれる元素のうち少なくとも１つの元素と同一の元素を含み、
　前記基準マークの底部において、前記多層反射膜に含まれる複数の膜のうち少なくとも一部の膜が収縮したシュリンク領域を有することを特徴とする、多層反射膜付き基板。 In order to solve the above-mentioned subject, the present invention has the following composition.
(Configuration 1)
A multilayer reflective film coated substrate comprising: a substrate; a multilayer reflective film for reflecting EUV light formed on the substrate; and a protective film formed on the multilayer reflective film,
It has a fiducial mark formed concavely on the surface of the protective film,
The surface layer of the reference mark contains an element identical to at least one of the elements contained in the protective film,
A multilayer reflective film coated substrate having a shrink region in which at least a part of a plurality of films included in the multilayer reflective film is contracted at the bottom of the reference mark.
（構成２）
　前記基準マークの表層は、Ｒｕを含む、構成１に記載の多層反射膜付き基板。 (Configuration 2)
The surface with the multilayer reflective film according to Configuration 1, wherein the surface layer of the reference mark includes Ru.
（構成３）
　前記基準マークの表層は、ＲｕＯ、ＲｕＮｂＯ、ＲｕＳｉ、及びＲｕＳｉＯ からなる群から選ばれる少なくとも１つを含む、構成２に記載の多層反射膜付き基板。 (Configuration 3)
The multilayer reflective film coated substrate according to Configuration 2, wherein the surface layer of the reference mark includes at least one selected from the group consisting of RuO, RuNbO, RuSi, and RuSiO 2.
（構成４）
　前記基準マークの底部において、前記多層反射膜に含まれる複数の膜のうち少なくとも一部の膜が互いに一体化したミキシング領域を有する、構成１から構成３のうちいずれかに記載の多層反射膜付き基板。 (Configuration 4)
At the bottom of the reference mark, the multilayer reflective film according to any one of Configurations 1 to 3, having a mixing area in which at least a part of the plurality of films included in the multilayer reflective film is integrated with each other substrate.
（構成５）
　前記基準マークの深さが３０ｎｍ以上５０ｎｍ以下である、構成１から構成４のうちいずれかに記載の多層反射膜付き基板。 (Configuration 5)
The multilayer reflective film coated substrate according to any one of Configurations 1 to 4, wherein the depth of the reference mark is 30 nm or more and 50 nm or less.
（構成６）
　前記多層反射膜の前記基板と反対側の表面層はＳｉを含む層である、構成１から構成５のうちいずれかに記載の多層反射膜付き基板。 (Configuration 6)
The substrate with a multilayer reflective film according to any one of Configurations 1 to 5, wherein the surface layer opposite to the substrate of the multilayer reflective film is a layer containing Si.
（構成７）
　構成１から構成６のうちいずれかに記載の多層反射膜付き基板と、当該多層反射膜付き基板の保護膜上に形成された、ＥＵＶ光を吸収する吸収体膜とを有する反射型マスクブランクであって、
　前記吸収体膜に前記基準マークの形状が転写されている、反射型マスクブランク。 (Configuration 7)
A reflective mask blank having a multilayer reflective film coated substrate according to any one of constitutions 1 to 6 and an absorber film for absorbing EUV light formed on a protective film of the multilayer reflective film coated substrate. There,
A reflective mask blank, wherein the shape of the reference mark is transferred to the absorber film.
（構成８）
　構成１から構成６のうちいずれかに記載の多層反射膜付き基板と、当該多層反射膜付き基板の保護膜上に形成された、ＥＵＶ光を吸収する吸収体膜パターンとを有する反射型マスクであって、
　前記吸収体膜パターンに前記基準マークの形状が転写されている、反射型マスク。 (Configuration 8)
A reflective mask having a multilayer reflective film coated substrate according to any one of constitutions 1 to 6 and an absorber film pattern formed on a protective film of the multilayer reflective film coated substrate and absorbing EUV light. There,
A reflective mask, wherein the shape of the reference mark is transferred to the absorber film pattern.
（構成９）
　構成８に記載の反射型マスクを使用して、半導体基板上に転写パターンを形成する工程を有する、半導体装置の製造方法。 (Configuration 9)
A method of manufacturing a semiconductor device, comprising the step of forming a transfer pattern on a semiconductor substrate using the reflective mask according to Configuration 8.
　本発明によれば、多層反射膜に基準マークを形成した場合でも、多層反射膜の表面が汚染されることを防止することのできる、多層反射膜付き基板、反射型マスクブランク、反射型マスク、及び半導体装置の製造方法を提供できる。また、基板の洗浄耐性が悪化することを防止することのできる、多層反射膜付き基板、反射型マスクブランク、反射型マスク、及び半導体装置の製造方法を提供できる。さらに、基準マークの加工に要する時間を短くすることのできる、多層反射膜付き基板、反射型マスクブランク、反射型マスク、及び半導体装置の製造方法を提供できる。 According to the present invention, even when the reference mark is formed on the multilayer reflective film, the multilayer reflective film coated substrate, the reflective mask blank, the reflective mask, and the like can prevent the surface of the multilayer reflective film from being contaminated. And a method of manufacturing a semiconductor device. In addition, it is possible to provide a multilayer reflective film coated substrate, a reflective mask blank, a reflective mask, and a method of manufacturing a semiconductor device, which can prevent the deterioration of the cleaning resistance of the substrate. Further, it is possible to provide a multilayer reflective film coated substrate, a reflective mask blank, a reflective mask, and a method of manufacturing a semiconductor device, which can shorten the time required for processing a reference mark.
多層反射膜付き基板の断面を示す模式図である。It is a schematic diagram which shows the cross section of a board | substrate with a multilayer reflective film. 多層反射膜付き基板の平面図、及び、基準マークの拡大図である。They are a top view of a substrate with a multilayer reflective film, and an enlarged view of a reference mark. 図２に示す基準マークのＢ－Ｂ線断面図である。FIG. 3 is a cross-sectional view of the reference mark shown in FIG. 2 along the line BB. 反射型マスクブランクの断面を示す模式図である。It is a schematic diagram which shows the cross section of a reflection type mask blank. 反射型マスクの製造方法を示す模式図である。It is a schematic diagram which shows the manufacturing method of a reflection type mask. パターン転写装置を示している。1 shows a pattern transfer device. 基準マークの断面のＴＥＭ画像である。It is a TEM image of the cross section of a fiducial mark.
　以下、本発明の実施形態について詳細に説明する。
［多層反射膜付き基板］
　図１は、本実施形態の多層反射膜付き基板の断面を示す模式図である。
　図１に示すように、多層反射膜付き基板１０は、基板１２と、露光光であるＥＵＶ光を反射する多層反射膜１４と、多層反射膜１４を保護するための保護膜１８とを備えている。基板１２の上に多層反射膜１４が形成され、多層反射膜１４の上に保護膜１８が形成されている。 Hereinafter, embodiments of the present invention will be described in detail.
[Multilayer reflective film coated substrate]
FIG. 1 is a schematic view showing a cross section of the multilayer reflective film coated substrate of this embodiment.
As shown in FIG. 1, the multilayer reflective film coated substrate 10 includes a substrate 12, a multilayer reflective film 14 that reflects EUV light that is exposure light, and a protective film 18 for protecting the multilayer reflective film 14. There is. A multilayer reflective film 14 is formed on the substrate 12, and a protective film 18 is formed on the multilayer reflective film 14.
　なお、本明細書において、基板や膜の「上に」とは、その基板や膜の上面に接触する場合だけでなく、その基板や膜の上面に接触しない場合も含む。すなわち、基板や膜の「上に」とは、その基板や膜の上方に新たな膜が形成される場合や、その基板や膜との間に他の膜が介在している場合等を含む。また、「上に」とは、必ずしも鉛直方向における上側を意味するものではなく、基板や膜などの相対的な位置関係を示しているに過ぎない。 In the present specification, "on" the substrate or film includes not only the case of contacting the upper surface of the substrate or film, but also the case of not contacting the upper surface of the substrate or film. That is, "on" the substrate or film includes the case where a new film is formed above the substrate or film, the case where another film is interposed between the substrate or film, etc. . Moreover, "on" does not necessarily mean the upper side in the vertical direction, but merely indicates the relative positional relationship of the substrate, the film, and the like.
　＜基板＞
　本実施形態の多層反射膜付き基板１０に使用される基板１２としては、ＥＵＶ露光の場合、露光時の熱による吸収体膜パターンの歪みを防止するため、０±５ｐｐｂ／℃の範囲内の低熱膨張係数を有するものが好ましく用いられる。この範囲の低熱膨張係数を有する素材としては、例えば、ＳｉＯ2－ＴｉＯ2系ガラス、多成分系ガラスセラミックス等を用いることができる。 <Board>
In the case of EUV exposure, the substrate 12 used for the multilayer reflective film coated substrate 10 of the present embodiment has a low thermal conductivity within the range of 0 ± 5 ppb / ° C. to prevent distortion of the absorber film pattern due to heat during exposure. Those having an expansion coefficient are preferably used. As a material having a low thermal expansion coefficient in this range, for example, SiO 2 —TiO 2 based glass, multicomponent glass ceramics, etc. can be used.
　基板１２の転写パターン（後述の吸収体膜パターンがこれに対応する）が形成される側の主表面は、平坦度を高めるために加工されることが好ましい。基板１２の主表面の平坦度を高めることによって、パターンの位置精度や転写精度を高めることができる。例えば、ＥＵＶ露光の場合、基板１２の転写パターンが形成される側の主表面の１３２ｍｍ×１３２ｍｍの領域において、平坦度が０．１μｍ以下であることが好ましく、更に好ましくは０．０５μｍ以下、特に好ましくは０．０３μｍ以下である。また、転写パターンが形成される側と反対側の主表面は、露光装置に静電チャックによって固定される面であって、その１４２ｍｍ×１４２ｍｍの領域において、平坦度が１μｍ以下、更に好ましくは０．５μｍ以下、特に好ましくは０．０３μｍ以下である。なお、本明細書において平坦度は、ＴＩＲ（Ｔｏｔａｌ　Ｉｎｄｉｃａｔｅｄ　Ｒｅａｄｉｎｇ）で示される表面の反り（変形量）を表す値で、基板表面を基準として最小二乗法で定められる平面を焦平面とし、この焦平面より上にある基板表面の最も高い位置と、焦平面より下にある基板表面の最も低い位置との高低差の絶対値である。 The main surface on the side where the transfer pattern of the substrate 12 (the absorber film pattern described later corresponds thereto) is preferably processed to enhance the flatness. By enhancing the flatness of the main surface of the substrate 12, it is possible to enhance the positional accuracy and transfer accuracy of the pattern. For example, in the case of EUV exposure, the flatness is preferably 0.1 μm or less, more preferably 0.05 μm or less, in a 132 mm × 132 mm region of the main surface of the substrate 12 on the side where the transfer pattern is formed. Preferably it is 0.03 micrometer or less. Further, the main surface opposite to the side on which the transfer pattern is formed is the surface fixed to the exposure apparatus by the electrostatic chuck, and the flatness is 1 μm or less, more preferably 0 in the 142 mm × 142 mm region. 0.5 μm or less, particularly preferably 0.03 μm or less. In the present specification, flatness is a value representing surface warpage (amount of deformation) indicated by TIR (Total Indicated Reading), and a plane determined by the least squares method with respect to the substrate surface is taken as a focal plane, It is the absolute value of the height difference between the highest position of the substrate surface above the plane and the lowest position of the substrate surface below the focal plane.
　ＥＵＶ露光の場合、基板１２の転写パターンが形成される側の主表面の表面粗さは、二乗平均平方根粗さ（ＲＭＳ）で０．１ｎｍ以下であることが好ましい。なお表面粗さは、原子間力顕微鏡で測定することができる。 In the case of EUV exposure, the surface roughness of the main surface on the side where the transfer pattern of the substrate 12 is formed is preferably 0.1 nm or less in root mean square roughness (RMS). The surface roughness can be measured by an atomic force microscope.
　基板１２は、その上に形成される膜（多層反射膜１４など）の膜応力による変形を防止するために、高い剛性を有していることが好ましい。特に、基板１２は、６５ＧＰａ以上の高いヤング率を有していることが好ましい。 The substrate 12 preferably has high rigidity in order to prevent deformation due to film stress of a film (such as the multilayer reflective film 14) formed thereon. In particular, the substrate 12 preferably has a high Young's modulus of 65 GPa or more.
　＜多層反射膜＞
　多層反射膜付き基板１０は、基板１２と、基板１２の上に形成された多層反射膜１４とを備えている。多層反射膜１４は、例えば、屈折率の異なる元素が周期的に積層された多層膜からなる。多層反射膜１４は、ＥＵＶ光を反射する機能を有している。 <Multilayer reflective film>
The multilayer reflective film coated substrate 10 includes a substrate 12 and a multilayer reflective film 14 formed on the substrate 12. The multilayer reflective film 14 is, for example, a multilayer film in which elements having different refractive indexes are periodically stacked. The multilayer reflective film 14 has a function of reflecting EUV light.
　一般的には、多層反射膜１４は、高屈折率材料である軽元素又はその化合物の薄膜（高屈折率層）と、低屈折率材料である重元素又はその化合物の薄膜（低屈折率層）とが交互に４０～６０周期程度積層された多層膜からなる。
　多層反射膜１４を形成するために、基板１２側から高屈折率層と低屈折率層をこの順に複数周期積層してもよい。この場合、１つの（高屈折率層／低屈折率層）の積層構造が、１周期となる。
　多層反射膜１４を形成するために、基板１２側から低屈折率層と高屈折率層をこの順に複数周期積層してもよい。この場合、１つの（低屈折率層／高屈折率層）の積層構造が、１周期となる。 Generally, the multilayer reflective film 14 is a thin film (high refractive index layer) of a light element or its compound which is a high refractive index material, and a thin film (a low refractive index layer) of a heavy element or its compound which is a low refractive index material And the like are alternately laminated in about 40 to 60 cycles.
In order to form the multilayer reflective film 14, a high refractive index layer and a low refractive index layer may be laminated in a plurality of cycles in this order from the substrate 12 side. In this case, the laminated structure of one (high refractive index layer / low refractive index layer) is one cycle.
In order to form the multilayer reflective film 14, a low refractive index layer and a high refractive index layer may be laminated in a plurality of cycles in this order from the substrate 12 side. In this case, the laminated structure of one (low refractive index layer / high refractive index layer) is one cycle.
　なお、多層反射膜１４の最上層、すなわち多層反射膜１４の基板１２と反対側の表面層は、高屈折率層であることが好ましい。基板１２側から高屈折率層と低屈折率層をこの順に積層する場合は、最上層が低屈折率層となる。しかし、低屈折率層が多層反射膜１４の表面である場合、低屈折率層が容易に酸化されることで多層反射膜の反射率が減少してしまうので、その低屈折率層の上に高屈折率層を形成する。一方、基板１２側から低屈折率層と高屈折率層をこの順に積層する場合は、最上層が高屈折率層となる。その場合は、最上層の高屈折率層が、多層反射膜１４の表面となる。 The uppermost layer of the multilayer reflective film 14, that is, the surface layer of the multilayer reflective film 14 opposite to the substrate 12 is preferably a high refractive index layer. When the high refractive index layer and the low refractive index layer are stacked in this order from the substrate 12 side, the uppermost layer is the low refractive index layer. However, when the low refractive index layer is the surface of the multilayer reflective film 14, the low refractive index layer is easily oxidized to reduce the reflectance of the multilayer reflective film, so that the low refractive index layer is formed on the low refractive index layer. Form a high refractive index layer. On the other hand, when the low refractive index layer and the high refractive index layer are laminated in this order from the substrate 12 side, the uppermost layer is the high refractive index layer. In that case, the uppermost high refractive index layer is the surface of the multilayer reflective film 14.
　本実施形態において、高屈折率層は、Ｓｉを含む層であってもよい。高屈折率層は、Ｓｉ単体を含んでもよく、Ｓｉ化合物を含んでもよい。Ｓｉ化合物は、Ｓｉと、Ｂ、Ｃ、Ｎ、及びＯからなる群から選択される少なくとも１つの元素を含んでもよい。Ｓｉを含む層を高屈折率層として使用することによって、ＥＵＶ光の反射率に優れた多層反射膜が得られる。 In the present embodiment, the high refractive index layer may be a layer containing Si. The high refractive index layer may contain Si alone or may contain a Si compound. The Si compound may contain Si and at least one element selected from the group consisting of B, C, N, and O. By using a layer containing Si as a high refractive index layer, a multilayer reflective film excellent in the reflectivity of EUV light can be obtained.
　本実施形態において、低屈折率材料としては、Ｍｏ、Ｒｕ、Ｒｈ、及びＰｔからなる群から選択される少なくとも１つの元素、あるいは、Ｍｏ、Ｒｕ、Ｒｈ、及びＰｔからなる群から選択される少なくとも１つの元素を含む合金を使用することができる。 In the present embodiment, as the low refractive index material, at least one element selected from the group consisting of Mo, Ru, Rh and Pt, or at least one selected from the group consisting of Mo, Ru, Rh and Pt Alloys containing one element can be used.
　例えば、波長１３～１４ｎｍのＥＵＶ光のための多層反射膜１４としては、好ましくは、Ｍｏ膜とＳｉ膜を交互に４０～６０周期程度積層したＭｏ／Ｓｉ多層膜を用いることができる。その他に、ＥＵＶ光の領域で使用される多層反射膜として、例えば、Ｒｕ／Ｓｉ周期多層膜、Ｍｏ／Ｂｅ周期多層膜、Ｍｏ化合物／Ｓｉ化合物周期多層膜、Ｓｉ／Ｎｂ周期多層膜、Ｓｉ／Ｍｏ／Ｒｕ周期多層膜、Ｓｉ／Ｍｏ／Ｒｕ／Ｍｏ周期多層膜、Ｓｉ／Ｒｕ／Ｍｏ／Ｒｕ周期多層膜などを用いることができる。露光波長を考慮して、多層反射膜の材料を選択することができる。 For example, as the multilayer reflective film 14 for EUV light with a wavelength of 13 to 14 nm, preferably, a Mo / Si multilayer film in which Mo films and Si films are alternately stacked for about 40 to 60 cycles can be used. Besides, as a multilayer reflective film used in the region of EUV light, for example, Ru / Si periodic multilayer film, Mo / Be periodic multilayer film, Mo compound / Si compound periodic multilayer film, Si / Nb periodic multilayer film, Si / A Mo / Ru periodic multilayer film, a Si / Mo / Ru / Mo periodic multilayer film, a Si / Ru / Mo / Ru periodic multilayer film or the like can be used. The material of the multilayer reflective film can be selected in consideration of the exposure wavelength.
　このような多層反射膜１４の単独での反射率は、例えば６５％以上である。多層反射膜１４の反射率の上限は、例えば７３％である。なお、多層反射膜１４に含まれる層の厚み及び周期は、ブラッグの法則を満たすように選択することができる。 The reflectivity of such a multilayer reflective film 14 alone is, for example, 65% or more. The upper limit of the reflectance of the multilayer reflective film 14 is, for example, 73%. The thickness and period of the layers included in the multilayer reflective film 14 can be selected so as to satisfy Bragg's law.
　多層反射膜１４は、公知の方法によって形成できる。多層反射膜１４は、例えば、イオンビームスパッタ法により形成できる。 The multilayer reflective film 14 can be formed by a known method. The multilayer reflective film 14 can be formed, for example, by ion beam sputtering.
　例えば、多層反射膜１４がＭｏ／Ｓｉ多層膜である場合、イオンビームスパッタ法により、Ｍｏターゲットを用いて、厚さ３ｎｍ程度のＭｏ膜を基板１２の上に形成する。次に、Ｓｉターゲットを用いて、厚さ４ｎｍ程度のＳｉ膜を形成する。このような操作を繰り返すことによって、Ｍｏ／Ｓｉ膜が４０～６０周期積層した多層反射膜１４を形成することができる。このとき、多層反射膜１４の基板１２と反対側の表面層は、Ｓｉを含む層（Ｓｉ膜）である。１周期のＭｏ／Ｓｉ膜の厚みは、７ｎｍとなる。 For example, when the multilayer reflective film 14 is a Mo / Si multilayer film, a Mo film having a thickness of about 3 nm is formed on the substrate 12 using an Mo target by ion beam sputtering. Next, a Si target is used to form a Si film having a thickness of about 4 nm. By repeating such an operation, it is possible to form a multilayer reflective film 14 in which Mo / Si films are laminated 40 to 60 cycles. At this time, the surface layer opposite to the substrate 12 of the multilayer reflective film 14 is a layer containing Si (Si film). The thickness of one cycle of Mo / Si film is 7 nm.
　＜保護膜＞
　本実施形態の多層反射膜付き基板１０は、多層反射膜１４の上に形成された保護膜１８を備えている。保護膜１８は、吸収体膜のパターニングあるいはパターン修正の際に、多層反射膜１４を保護する機能を有している。保護膜１８は、多層反射膜１４と後述の吸収体膜との間に設けられる。 <Protective film>
The multilayer reflective film coated substrate 10 of the present embodiment is provided with a protective film 18 formed on the multilayer reflective film 14. The protective film 18 has a function of protecting the multilayer reflective film 14 in patterning or pattern correction of the absorber film. The protective film 18 is provided between the multilayer reflective film 14 and an absorber film described later.
　保護膜１８の材料としては、例えば、Ｒｕ、Ｒｕ－（Ｎｂ、Ｚｒ、Ｙ、Ｂ、Ｔｉ、Ｌａ、Ｍｏ、Ｃｏ又はＲｅ）化合物、Ｓｉ－（Ｒｕ、Ｒｈ、Ｃｒ又はＢ）化合物、Ｓｉ、Ｚｒ、Ｎｂ、Ｌａ、Ｂ等の材料を使用することができる。また、これらに窒素、酸素又は炭素を添加した化合物を用いることができる。これらのうち、ルテニウム（Ｒｕ）を含む材料を適用すると、多層反射膜の反射率特性がより良好となる。具体的には、保護膜１８の材料は、Ｒｕ、又は、Ｒｕ－（Ｎｂ、Ｚｒ、Ｙ、Ｂ、Ｔｉ、Ｌａ、Ｍｏ、Ｃｏ又はＲｅ）化合物であることが好ましい。保護膜１８の厚みは、例えば、１ｎｍ～５ｎｍである。保護膜１８は、公知の方法によって形成できる。保護膜１８は、例えば、マグネトロンスパッタリング法やイオンビームスパッタ法によって形成できる。 As a material of the protective film 18, for example, Ru, Ru- (Nb, Zr, Y, B, Ti, La, Mo, Co or Re) compound, Si- (Ru, Rh, Cr or B) compound, Si, Materials such as Zr, Nb, La, B and the like can be used. Moreover, the compound which added nitrogen, oxygen, or carbon to these can be used. Among these, when a material containing ruthenium (Ru) is applied, the reflectance characteristics of the multilayer reflective film become better. Specifically, the material of the protective film 18 is preferably Ru or Ru- (Nb, Zr, Y, B, Ti, La, Mo, Co or Re) compound. The thickness of the protective film 18 is, for example, 1 nm to 5 nm. The protective film 18 can be formed by a known method. The protective film 18 can be formed by, for example, a magnetron sputtering method or an ion beam sputtering method.
　多層反射膜付き基板１０は、さらに、基板１２の多層反射膜１４が形成されている側とは反対側の主表面上に、裏面導電膜を有してもよい。裏面導電膜は、静電チャックによって多層反射膜付き基板１０あるいは反射型マスクブランクを吸着する際に使用される。 The multilayer reflective film coated substrate 10 may further have a back surface conductive film on the main surface of the substrate 12 opposite to the side on which the multilayer reflective film 14 is formed. The back surface conductive film is used when adsorbing the multilayer reflective film coated substrate 10 or the reflective mask blank by an electrostatic chuck.
　多層反射膜付き基板１０は、基板１２と多層反射膜１４との間に形成された下地膜を有してもよい。下地膜は、例えば、基板１２の表面の平滑性向上の目的で形成される。下地膜は、例えば、欠陥低減、多層反射膜の反射率向上、多層反射膜の応力補正等の目的で形成される。 The multilayer reflective film coated substrate 10 may have a base film formed between the substrate 12 and the multilayer reflective film 14. The underlayer is formed, for example, for the purpose of improving the smoothness of the surface of the substrate 12. The undercoat film is formed, for example, for the purpose of defect reduction, improvement of the reflectance of the multilayer reflective film, and stress correction of the multilayer reflective film.
＜基準マーク＞
　図２は、本実施形態の多層反射膜付き基板１０の平面図である。
　図２に示すように、略矩形状の多層反射膜付き基板１０の４つの角部の近傍には、欠陥情報における欠陥位置の基準として使用できる基準マーク２０がそれぞれ形成されている。なお、基準マーク２０が４つ形成されている例を示しているが、基準マーク２０の数は４つに限らず、３つ以下でもよいし、５つ以上でもよい。 <Reference mark>
FIG. 2 is a plan view of the multilayer reflective film coated substrate 10 of the present embodiment.
As shown in FIG. 2, in the vicinity of four corners of the substantially rectangular multilayer reflective film coated substrate 10, reference marks 20 which can be used as a reference of the defect position in the defect information are respectively formed. Although the example in which four reference marks 20 are formed is shown, the number of reference marks 20 is not limited to four, and may be three or less, or five or more.
　図２に示す多層反射膜付き基板１０において、破線Ａの内側の領域（１３２ｍｍ×１３２ｍｍの領域）は、反射型マスクを製造するときに吸収体膜パターンが形成されるパターン形成領域である。破線Ａの外側の領域は、反射型マスクを製造するときに吸収体膜パターンが形成されない領域である。基準マーク２０は、好ましくは、吸収体膜パターンが形成されない領域、すなわち、破線Ａの外側の領域に形成される。 In the multilayer reflective film coated substrate 10 shown in FIG. 2, the region inside the broken line A (a region of 132 mm × 132 mm) is a pattern formation region in which an absorber film pattern is formed when the reflective mask is manufactured. The area outside the broken line A is an area where the absorber film pattern is not formed when the reflective mask is manufactured. The reference mark 20 is preferably formed in the area where the absorber film pattern is not formed, that is, the area outside the broken line A.
　図２に示すように、基準マーク２０は、略十字型形状を有している。略十字型形状を有する基準マーク２０の一本の線の幅Ｗは、例えば、２００ｎｍ以上１０μｍ以下である。基準マーク２０の一本の線の長さＬは、例えば、１００μｍ以上１５００μｍ以下である。図２では、略十字型形状を有する基準マーク２０の例を示しているが、基準マーク２０の形状はこれに限定されない。基準マーク２０の形状は、例えば、平面視略Ｌ字型であってもよい。 As shown in FIG. 2, the reference mark 20 has a substantially cruciform shape. The width W of one line of the reference mark 20 having a substantially cruciform shape is, for example, 200 nm or more and 10 μm or less. The length L of one line of the reference mark 20 is, for example, not less than 100 μm and not more than 1500 μm. Although FIG. 2 shows an example of the reference mark 20 having a substantially cross shape, the shape of the reference mark 20 is not limited to this. The shape of the reference mark 20 may be, for example, a substantially L-shape in plan view.
　図３は、図２に示す基準マーク２０のＢ－Ｂ線断面図であり、基準マーク２０の断面構造を模式的に示している。
　図３に示すように、本実施形態の多層反射膜付き基板１０では、多層反射膜付き基板１０の断面（多層反射膜付き基板１０の主表面に垂直な断面）を見たときに、基準マーク２０が保護膜１８の表面に凹状に形成されている。ここでいう「凹状」とは、多層反射膜付き基板１０の断面を見たときに、基準マーク２０が保護膜１８よりも下方に向けて例えば段差状あるいは湾曲状に凹むようにして形成されているという意味である。 FIG. 3 is a cross-sectional view taken along the line BB of the reference mark 20 shown in FIG. 2, and schematically shows the cross-sectional structure of the reference mark 20. As shown in FIG.
As shown in FIG. 3, in the multilayer reflective film coated substrate 10 of the present embodiment, a reference mark when looking at a cross section of the multilayer reflective film coated substrate 10 (cross section perpendicular to the main surface of the multilayer reflective film coated substrate 10). 20 are formed in a concave shape on the surface of the protective film 18. The term "concave" as used herein means that when the cross section of the multilayer reflective film coated substrate 10 is viewed, the reference mark 20 is formed to be recessed, for example, in a step-like shape or in a curved shape downward from the protective film 18 It is a meaning.
　基準マーク２０の表層２２には、保護膜１８に含まれる元素のうち少なくとも１つの元素と同一の元素が含まれている。例えば、基準マーク２０の表層２２には、Ｒｕ、Ｎｂ、Ｚｒ、Ｙ、Ｂ、Ｔｉ、Ｌａ、Ｍｏ、Ｃｏ、Ｒｅ、Ｓｉ、Ｒｈ、及びＣｒからなる群から選択される少なくとも１つの元素が含まれている。基準マーク２０の表層２２には、好ましくは、保護膜１８に含まれる元素と同一の元素であるルテニウム（Ｒｕ）が含まれている。基準マーク２０の表層２２に含まれている元素の種類は、例えば、ＥＤＸ（エネルギー分散型Ｘ線分析）によって特定することができる。 The surface layer 22 of the reference mark 20 contains the same element as at least one of the elements contained in the protective film 18. For example, the surface layer 22 of the reference mark 20 contains at least one element selected from the group consisting of Ru, Nb, Zr, Y, B, Ti, La, Mo, Co, Re, Si, Rh, and Cr. It is done. The surface layer 22 of the reference mark 20 preferably contains ruthenium (Ru) which is the same element as the element contained in the protective film 18. The types of elements contained in the surface layer 22 of the reference mark 20 can be identified by, for example, EDX (energy dispersive X-ray analysis).
　基準マーク２０の表層２２には、保護膜１８に含まれる元素のうち少なくとも１つの元素と同一の元素の酸化物が含まれていてもよい。例えば、基準マーク２０の表層２２には、Ｒｕ、Ｒｕ－（Ｎｂ、Ｚｒ、Ｙ、Ｂ、Ｔｉ、Ｌａ、Ｍｏ、Ｃｏ又はＲｅ）化合物、Ｓｉ－（Ｒｕ、Ｒｈ、Ｃｒ又はＢ）化合物、Ｓｉ、Ｚｒ、Ｎｂ、Ｌａ、及びＢからなる群から選択される少なくとも１つの元素又は化合物の酸化物が含まれていてもよい。 The surface layer 22 of the reference mark 20 may contain an oxide of the same element as at least one of the elements contained in the protective film 18. For example, the surface layer 22 of the reference mark 20 may be Ru, Ru- (Nb, Zr, Y, B, Ti, La, Mo, Co or Re) compound, Si- (Ru, Rh, Cr or B) compound, Si An oxide of at least one element or compound selected from the group consisting of Zr, Nb, La, and B may be included.
　保護膜１８にＲｕ又はＲｕＮｂが含まれている場合、基準マーク２０の表層２２には、Ｒｕ又はＲｕＮｂの酸化物が含まれてもよい。例えば、基準マーク２０の表層２２には、ＲｕＯ及びＲｕＮｂＯのうち少なくとも１つが含まれていてもよい。 When the protective film 18 contains Ru or RuNb, the surface layer 22 of the reference mark 20 may contain an oxide of Ru or RuNb. For example, the surface layer 22 of the reference mark 20 may include at least one of RuO and RuNbO.
　なお、基準マーク２０の「表層２２」とは、例えば、基準マーク２０の表面から深さ２ｎｍまでの領域のことを意味する。
　表層２２には、保護膜１８に含まれる元素と同一の元素が含まれる。保護膜１８に含まれる元素と同一の元素は、表層２２の全面に含まれてもよく、表層２２の一部に含まれてもよい。好ましくは、保護膜１８に含まれる元素と同一の元素は、表層２２の全面に含まれる。この場合、多層反射膜１４に含まれる材料が露出することがなく、多層反射膜付き基板１０の洗浄耐性が悪化するのを防止することができる。 The “surface layer 22” of the reference mark 20 means, for example, a region from the surface of the reference mark 20 to a depth of 2 nm.
The surface layer 22 contains the same element as the element contained in the protective film 18. The same element as the element contained in the protective film 18 may be contained in the entire surface of the surface layer 22 or may be contained in a part of the surface layer 22. Preferably, the same element as the element contained in the protective film 18 is contained in the entire surface layer 22. In this case, the material contained in the multilayer reflective film 14 is not exposed, and the cleaning resistance of the multilayer reflective film coated substrate 10 can be prevented from being deteriorated.
　保護膜１８にＲｕ又はＲｕ化合物が含まれている場合には、多層反射膜１４の基板１２と反対側の表面層１４ａは、Ｓｉを含む層（Ｓｉ膜）であることが好ましい。基準マーク２０をレーザ加工する際の熱によって、基準マーク２０の表層２２においてＲｕとＳｉが反応してＲｕＳｉが形成されるため、多層反射膜付き基板１０の洗浄耐性が向上するためである。 In the case where the protective film 18 contains Ru or a Ru compound, the surface layer 14 a of the multilayer reflective film 14 on the opposite side to the substrate 12 is preferably a layer containing Si (Si film). This is because Ru and Si react with each other in the surface layer 22 of the reference mark 20 to form RuSi by heat when the reference mark 20 is laser-processed, so that the cleaning resistance of the multilayer reflective film coated substrate 10 is improved.
　保護膜１８にＲｕ又はＲｕ化合物が含まれ、多層反射膜１４の表面層１４ａがＳｉを含む層の場合、基準マーク２０の表層２２には、例えば、ＲｕＳｉ及びＲｕＳｉＯのうち少なくとも１つが含まれていてもよい。 In the case where the protective film 18 contains Ru or a Ru compound, and the surface layer 14a of the multilayer reflective film 14 is a layer containing Si, the surface layer 22 of the reference mark 20 contains, for example, at least one of RuSi and RuSiO. May be
　図３に示すように、基準マーク２０の底部には、多層反射膜１４に含まれる複数の膜のうち少なくとも一部の膜が収縮したシュリンク領域２４が形成されている。基準マーク２０の底部とは、凹状の表層２２よりも下方であって、基板１２の上面までの領域を意味する。 As shown in FIG. 3, at the bottom of the reference mark 20, a shrink region 24 in which at least a part of the plurality of films included in the multilayer reflective film 14 is contracted is formed. The bottom of the reference mark 20 means an area below the concave surface layer 22 up to the top surface of the substrate 12.
　シュリンク領域２４では、多層反射膜１４に含まれる複数の膜のうち、少なくとも一部の膜の厚みが収縮している。例えば、多層反射膜１４が、厚さ３ｎｍのＭｏ膜と、厚さ４ｎｍのＳｉ膜を周期的に積層したＭｏ／Ｓｉ多層膜である場合、１周期のＭｏ／Ｓｉ膜の厚みは、７ｎｍである。シュリンク領域２４では、例えば、１周期のＭｏ／Ｓｉ膜の厚みが、７ｎｍから６ｎｍに収縮している。この場合、収縮前の厚みは７ｎｍであり、収縮後の厚みは６ｎｍであるから、多層反射膜１４の厚みの収縮率は約８６％である。シュリンク領域２４において、多層反射膜１４の厚みの収縮率は、好ましくは７５％以上９５％以下であり、より好ましくは、８０％以上９０％以下である。 In the shrink region 24, the thickness of at least a part of the plurality of films included in the multilayer reflective film 14 is shrunk. For example, in the case where the multilayer reflective film 14 is a Mo / Si multilayer film in which a 3 nm thick Mo film and a 4 nm thick Si film are periodically stacked, the thickness of one cycle Mo / Si film is 7 nm. is there. In the shrink region 24, for example, the thickness of one cycle of the Mo / Si film shrinks from 7 nm to 6 nm. In this case, since the thickness before contraction is 7 nm and the thickness after contraction is 6 nm, the contraction ratio of the thickness of the multilayer reflective film 14 is about 86%. In the shrink region 24, the contraction rate of the thickness of the multilayer reflective film 14 is preferably 75% to 95%, and more preferably 80% to 90%.
　シュリンク領域２４では、多層反射膜１４に含まれる複数の膜のうち少なくとも一部の膜が収縮しているが、多層反射膜１４の積層構造は維持されている。多層反射膜１４の積層構造が維持されていることは、例えば、多層反射膜付き基板１０の断面のＴＥＭ画像によって容易に確認できる。 In the shrink region 24, at least a part of the plurality of films included in the multilayer reflective film 14 is shrunk, but the multilayer structure of the multilayer reflective film 14 is maintained. That the laminated structure of the multilayer reflective film 14 is maintained can be easily confirmed, for example, by a TEM image of a cross section of the multilayer reflective film-attached substrate 10.
　図３に示すように、基準マーク２０の底部の中央部付近であって、シュリンク領域２４の上方には、多層反射膜１４に含まれる複数の膜のうち少なくとも一部の膜が互いに一体化したミキシング領域２６が形成されている。ミキシング領域２６では、多層反射膜１４に含まれる複数の膜が、基準マーク２０をレーザ加工した際の熱によって互いに反応して一体化している。例えば、多層反射膜１４がＭｏ／Ｓｉ多層膜である場合、ミキシング領域２６では、Ｍｏ膜とＳｉ膜が反応してＭｏＳｉが生成されている。 As shown in FIG. 3, at least a part of the plurality of films included in the multilayer reflective film 14 is integrated with each other in the vicinity of the central portion of the bottom of the reference mark 20 and above the shrink region 24. A mixing area 26 is formed. In the mixing area 26, a plurality of films included in the multilayer reflective film 14 react with each other by heat generated when the reference mark 20 is laser-processed and integrated. For example, when the multilayer reflective film 14 is a Mo / Si multilayer film, the Mo film and the Si film react with each other in the mixing region 26 to generate MoSi.
　ミキシング領域２６は、基準マーク２０の底部の中央部付近に形成されやすいが、中央部以外の部分に形成されることもある。ミキシング領域２６の厚さは、２００ｎｍ以下が好ましく、１５０ｎｍ以下がより好ましい。この場合、基準マーク２０の表層２２に保護膜１８が残存し、表層２２中に保護膜１８の元素が含まれやすくなる。ここでいうミキシング領域２６の厚さとは、ミキシング領域２６の垂直方向の厚さの最大値を意味する。また、図３ではミキシング領域２６が形成されている例を示しているが、レーザ加工の条件等によっては、ミキシング領域２６が形成されないこともある。 The mixing area 26 is likely to be formed near the central part of the bottom of the reference mark 20, but may be formed in parts other than the central part. 200 nm or less is preferable and, as for the thickness of the mixing area | region 26, 150 nm or less is more preferable. In this case, the protective film 18 remains on the surface layer 22 of the reference mark 20, and the element of the protective film 18 is easily included in the surface layer 22. The thickness of the mixing area 26 mentioned here means the maximum value of the thickness in the vertical direction of the mixing area 26. Although FIG. 3 shows an example in which the mixing area 26 is formed, the mixing area 26 may not be formed depending on the conditions of the laser processing and the like.
　ミキシング領域２６では、多層反射膜１４に含まれる複数の膜が一体化しているため、多層反射膜１４の積層構造は維持されていない。多層反射膜１４に含まれる複数の膜が一体化していることは、例えば、多層反射膜付き基板１０の断面のＴＥＭ画像によって容易に確認できる。 In the mixing area 26, since the plurality of films included in the multilayer reflective film 14 are integrated, the multilayer structure of the multilayer reflective film 14 is not maintained. The integration of the plurality of films included in the multilayer reflective film 14 can be easily confirmed by, for example, a TEM image of a cross section of the multilayer reflective film-coated substrate 10.
　図３に示すように、凹状に形成された基準マーク２０の深さＤは、好ましくは、３０ｎｍ以上５０ｎｍである。深さＤとは、保護膜１８の表面から、基準マーク２０の底部の最も深い位置までの垂直方向の距離のことを意味する。 As shown in FIG. 3, the depth D of the concave reference mark 20 is preferably 30 nm or more and 50 nm. The depth D means the vertical distance from the surface of the protective film 18 to the deepest position at the bottom of the reference mark 20.
　図３に示すように、凹状に形成された基準マーク２０の傾斜角θは、好ましくは２５度未満であり、より好ましくは３度以上１０度以下である。傾斜角θとは、基準マーク２０の断面を見たときに、基準マーク２０の表層２２の延長線２２ａと、保護膜１８の表面１８ａとがなす角度を意味する。 As shown in FIG. 3, the inclination angle θ of the concave reference mark 20 is preferably less than 25 degrees, and more preferably 3 degrees or more and 10 degrees or less. The inclination angle θ means the angle between the extension line 22 a of the surface layer 22 of the reference mark 20 and the surface 18 a of the protective film 18 when the cross section of the reference mark 20 is viewed.
　基準マーク２０の形成方法は、特に制限されない。基準マーク２０は、例えば、保護膜１８の表面にレーザ加工によって形成することができる。レーザ加工の条件は、例えば、以下の通りである。
　レーザの種類（波長）：紫外線～可視光領域。例えば、波長４０５ｎｍの半導体レーザ。
　レーザ出力：１～１２０　ｍＷ
　スキャン速度：０．１～２０　ｍｍ／ｓ
　パルス周波数：１～１００　ＭＨｚ
　パルス幅：３ｎｓ～１０００ｓ The method of forming the reference mark 20 is not particularly limited. The reference mark 20 can be formed, for example, by laser processing on the surface of the protective film 18. The conditions for laser processing are, for example, as follows.
Laser type (wavelength): Ultraviolet to visible light region. For example, a semiconductor laser with a wavelength of 405 nm.
Laser power: 1 to 120 mW
Scanning speed: 0.1 to 20 mm / s
Pulse frequency: 1 to 100 MHz
Pulse width: 3ns to 1000s
　基準マーク２０をレーザ加工する際に使用するレーザは、連続波でもよく、パルス波でもよい。パルス波を用いた場合、連続波と比較して、基準マーク２０の深さＤが同程度であっても、基準マーク２０の幅Ｗをより小さくすることが可能である。また、パルス波を用いた場合、連続波と比較して、基準マーク２０の傾斜角θを大きくすることが可能である。このため、パルス波を用いた場合、連続波と比較して、よりコントラストが大きく、欠陥検査装置や電子線描画装置によって検出し易い基準マーク２０を形成することができる。 The laser used for laser processing the reference mark 20 may be a continuous wave or a pulse wave. When a pulse wave is used, the width W of the reference mark 20 can be made smaller than that of the continuous wave, even if the depth D of the reference mark 20 is approximately the same. When a pulse wave is used, the inclination angle θ of the reference mark 20 can be made larger than that of a continuous wave. Therefore, when the pulse wave is used, it is possible to form the reference mark 20 which has a larger contrast than the continuous wave and is easy to detect by the defect inspection apparatus or the electron beam drawing apparatus.
　基準マーク２０は、例えば、ＦＭ（フィデュシャルマーク）として使用できる。ＦＭとは、電子線描画装置によってパターンを描画する際に、欠陥座標の基準として使用されるマークである。ＦＭは、通常、図２に示すような十字型形状である。 The fiducial mark 20 can be used, for example, as an FM (fiducial mark). The FM is a mark used as a reference of defect coordinates when drawing a pattern by the electron beam drawing apparatus. The FM is usually in the shape of a cross as shown in FIG.
　例えば、多層反射膜付き基板１０に基準マーク２０を形成した場合には、欠陥検査装置によって、基準マーク２０の座標及び欠陥の座標を高精度に取得する。次に、多層反射膜付き基板１０の保護膜１８の上に、吸収体膜を形成する。次に、吸収体膜の上に、レジスト膜を形成する。吸収体膜とレジスト膜との間には、ハードマスク膜（あるいはエッチングマスク膜）が形成されてもよい。多層反射膜付き基板１０の保護膜１８の上に形成された凹状の基準マーク２０は、吸収体膜及びレジスト膜に転写されるか、又は、吸収体膜、ハードマスク膜及びレジスト膜に転写される。そして、電子線描画装置によってレジスト膜にパターンを描画する際に、レジスト膜に転写された基準マーク２０が、欠陥位置の基準であるＦＭとして使用される。 For example, when the reference mark 20 is formed on the multilayer reflective film coated substrate 10, the coordinates of the reference mark 20 and the coordinates of the defect are acquired with high accuracy by the defect inspection apparatus. Next, an absorber film is formed on the protective film 18 of the multilayer reflective film coated substrate 10. Next, a resist film is formed on the absorber film. A hard mask film (or an etching mask film) may be formed between the absorber film and the resist film. The concave reference mark 20 formed on the protective film 18 of the multilayer reflective film coated substrate 10 is transferred to an absorber film and a resist film, or transferred to an absorber film, a hard mask film and a resist film. Ru. Then, when a pattern is drawn on the resist film by the electron beam drawing apparatus, the reference mark 20 transferred to the resist film is used as the FM which is the reference of the defect position.
　したがって、多層反射膜付き基板１０に形成された基準マーク２０は、欠陥検査装置によって検出可能な程度に高いコントラストを有している必要がある。欠陥検査装置としては、例えば、検査光源波長が２６６ｎｍであるレーザーテック社製のＥＵＶ露光用のマスク・サブストレート／ブランク欠陥検査装置「MAGICSM7360」、検査光源波長が１９３ｎｍであるＫＬＡ－Ｔｅｎｃｏｒ社製のＥＵＶ・マスク／ブランク欠陥検査装置「Teron600シリーズ、例えばTeron610」、検査光源波長が露光光源波長の１３．５ｎｍと同じであるＡＢＩ（Actinic Blank Inspection）装置がある。また、吸収体膜及びその上のレジスト膜に転写された基準マーク２０は、電子線描画装置によって検出可能な程度に高いコントラストを有している必要がある。さらに、基準マーク２０は、座標計測器によって検出可能な程度に高いコントラストを有していることが好ましい。座標計測器は、欠陥検査装置によって取得された欠陥の座標を、電子線描画装置の基準座標に変換することができる。したがって、多層反射膜付き基板１０を提供されたユーザーは、基準マーク２０に基づき、欠陥検査装置により特定した欠陥位置と、描画データとを容易かつ高精度に照合することが可能となる。 Therefore, the reference marks 20 formed on the multilayer reflective film coated substrate 10 need to have high contrast that is detectable by the defect inspection apparatus. As a defect inspection apparatus, for example, a mask substrate / blank defect inspection apparatus “MAGICSM 7360” for EUV exposure manufactured by Lasertec having an inspection light source wavelength of 266 nm, an EUV manufactured by KLA-Tencor having an inspection light source wavelength of 193 nm Mask / blank defect inspection apparatus “Teron 600 series, for example, Teron 610”, there is an ABI (Actinic Blank Inspection) apparatus whose inspection light source wavelength is the same as 13.5 nm of exposure light source wavelength. In addition, the reference mark 20 transferred to the absorber film and the resist film thereon needs to have a contrast high enough to be detected by the electron beam drawing apparatus. Furthermore, it is preferable that the reference mark 20 have a contrast high enough to be detected by the coordinate measuring device. The coordinate measuring device can convert the coordinates of the defect acquired by the defect inspection device into reference coordinates of the electron beam drawing device. Therefore, the user provided with the multilayer reflective film coated substrate 10 can easily and precisely match the defect position identified by the defect inspection apparatus with the drawing data based on the reference mark 20.
　基準マーク２０をＦＭとして使用することにより、欠陥座標を高精度に管理することができる。例えば、電子線描画装置によってＦＭを検出することにより、欠陥座標を電子線描画装置の座標系に変換することができる。そして、例えば、欠陥が吸収体膜パターンの下に配置するように、電子線描画装置によって描画されるパターンの描画データを補正することができる。これにより、最終的に製造される反射型マスクへの欠陥による影響を低減することができる（この手法は、欠陥緩和（defect mitigation）プロセスと呼ばれる）。 By using the fiducial mark 20 as an FM, defect coordinates can be managed with high accuracy. For example, the defect coordinates can be converted to the coordinate system of the electron beam drawing apparatus by detecting the FM by the electron beam drawing apparatus. Then, for example, the drawing data of the pattern drawn by the electron beam drawing apparatus can be corrected such that the defect is disposed below the absorber film pattern. This can reduce the influence of defects on the reflective mask finally manufactured (this method is called a defect mitigation process).
　基準マーク２０は、ＡＭ（アライメントマーク）としても使用できる。ＡＭは、欠陥検査装置で多層反射膜１４上の欠陥を検査した際に欠陥座標の基準として使用できるマークである。しかし、ＡＭは、電子線描画装置によってパターンを描画する際には直接使用されない。ＡＭは、円形、四角形、又は十字型等の形状とすることができる。 The fiducial mark 20 can also be used as an AM (alignment mark). AM is a mark that can be used as a reference of the defect coordinates when the defect inspection apparatus inspects a defect on the multilayer reflective film 14. However, AM is not directly used when drawing a pattern by an electron beam drawing apparatus. AM can be in the shape of a circle, a square, a cross, or the like.
　多層反射膜１４上にＡＭを形成した場合には、多層反射膜１４上の吸収体膜にＦＭを形成するとともに、ＡＭ上の吸収体膜を一部除去することが好ましい。ＡＭは、欠陥検査装置及び座標計測器で検出可能である。ＦＭは、座標計測器及び電子線描画装置で検出可能である。ＡＭとＦＭの間で相対的に座標を管理することによって、欠陥座標を高精度に管理することができる。 When AM is formed on the multilayer reflective film 14, it is preferable to form FM on the absorber film on the multilayer reflective film 14 and to partially remove the absorber film on the AM. AM can be detected by a defect inspection apparatus and a coordinate measuring instrument. The FM can be detected by a coordinate measuring instrument and an electron beam drawing apparatus. By managing coordinates relatively between AM and FM, defect coordinates can be managed with high accuracy.
［反射型マスクブランク］
　図４は、本実施形態の反射型マスクブランク３０の断面を示す模式図である。上述の多層反射膜付き基板１０の保護膜１８上にＥＵＶ光を吸収する吸収体膜２８を形成することによって、本実施形態の反射型マスクブランク３０を製造できる。 [Reflective mask blank]
FIG. 4 is a schematic view showing a cross section of the reflective mask blank 30 of the present embodiment. The reflective mask blank 30 of this embodiment can be manufactured by forming the absorber film 28 that absorbs EUV light on the protective film 18 of the multilayer reflective film coated substrate 10 described above.
　吸収体膜２８は、露光光であるＥＵＶ光を吸収する機能を有する。すなわち、多層反射膜１４のＥＵＶ光に対する反射率と、吸収体膜２８のＥＵＶ光に対する反射率との差は、所定値以上となっている。例えば、吸収体膜２８のＥＵＶ光に対する反射率は、０．１％以上４０％以下である。多層反射膜１４で反射された光と、吸収体膜２８で反射された光との間には、所定の位相差があってもよい。なお、この場合、反射型マスクブランク３０における吸収体膜２８は、位相シフト膜と呼ばれることがある。 The absorber film 28 has a function of absorbing EUV light which is exposure light. That is, the difference between the reflectance of the multilayer reflective film 14 to EUV light and the reflectance of the absorber film 28 to EUV light is equal to or greater than a predetermined value. For example, the reflectance of the absorber film 28 to EUV light is 0.1% or more and 40% or less. There may be a predetermined phase difference between the light reflected by the multilayer reflective film 14 and the light reflected by the absorber film 28. In this case, the absorber film 28 in the reflective mask blank 30 may be called a phase shift film.
　吸収体膜２８は、ＥＵＶ光を吸収する機能を有し、かつ、エッチング等により除去可能であることが好ましい。吸収体膜２８は、塩素（Ｃｌ）系ガスやフッ素（Ｆ）系ガスによるドライエッチングでエッチング可能であることが好ましい。このような機能を吸収体膜２８が有する限り、吸収体膜２８の材料は、特に制限されない。 The absorber film 28 preferably has a function of absorbing EUV light and can be removed by etching or the like. The absorber film 28 is preferably etchable by dry etching using a chlorine (Cl) -based gas or a fluorine (F) -based gas. The material of the absorber film 28 is not particularly limited as long as the absorber film 28 has such a function.
　吸収体膜２８は、単層でもよく、積層構造を有してもよい。吸収体膜２８が積層構造を有する場合、同一材料からなる複数の膜が積層されてもよく、異なる材料からなる複数の膜が積層されてもよい。吸収体膜２８が積層構造を有する場合、材料や組成が膜の厚み方向に段階的及び／又は連続的に変化してもよい。 The absorber film 28 may be a single layer or may have a laminated structure. When the absorber film 28 has a laminated structure, a plurality of films made of the same material may be laminated, or a plurality of films made of different materials may be laminated. When the absorber film 28 has a laminated structure, the material and the composition may change stepwise and / or continuously in the thickness direction of the film.
　吸収体膜２８の材料は、例えば、タンタル（Ｔａ）単体、又は、Ｔａを含む材料が好ましい。Ｔａを含む材料は、例えば、ＴａとＢを含む材料、ＴａとＮを含む材料、ＴａとＢと、Ｏ及びＮのうち少なくとも１つとを含む材料、ＴａとＳｉを含む材料、ＴａとＳｉとＮを含む材料、ＴａとＧｅを含む材料、ＴａとＧｅとＮを含む材料、ＴａとＰｄを含む材料、ＴａとＲｕを含む材料、ＴａとＴｉを含む材料等である。 The material of the absorber film 28 is preferably, for example, tantalum (Ta) alone or a material containing Ta. The material containing Ta is, for example, a material containing Ta and B, a material containing Ta and N, a material containing Ta and B, and at least one of O and N, a material containing Ta and Si, Ta and Si A material containing N, a material containing Ta and Ge, a material containing Ta, Ge and N, a material containing Ta and Pd, a material containing Ta and Ru, a material containing Ta and Ti, etc.
　吸収体膜２８は、例えば、Ｎｉ単体、Ｎｉを含む材料、Ｃｒ単体、Ｃｒを含む材料、Ｒｕ単体、Ｒｕを含む材料、Ｐｄ単体、Ｐｄを含む材料、Ｍｏ単体、及び、Ｍｏを含有する材料からなる群から選択される少なくとも１つを含んでもよい。 The absorber film 28 includes, for example, a single Ni, a material containing Ni, a single Cr, a material containing Cr, a single Ru, a material containing Ru, a single Pd, a material containing Pd, a single Mo, and a material containing Mo. And at least one selected from the group consisting of
　吸収体膜２８の厚みは、好ましくは、３０ｎｍ～１００ｎｍである。
　吸収体膜２８は、公知の方法、例えば、マグネトロンスパッタリング法や、イオンビームスパッタリング法などによって形成することができる。 The thickness of the absorber film 28 is preferably 30 nm to 100 nm.
The absorber film 28 can be formed by a known method, for example, a magnetron sputtering method, an ion beam sputtering method, or the like.
　本実施形態の反射型マスクブランク３０において、吸収体膜２８の上に、レジスト膜３２が形成されてもよい。図４にはこの態様が示されている。レジスト膜３２に電子線描画装置によってパターンを描画及び露光した後、現像工程を経ることによって、レジストパターンを形成することができる。このレジストパターンをマスクとして吸収体膜２８にドライエッチングを行うことによって、吸収体膜２８にパターンを形成することができる。 In the reflective mask blank 30 of the present embodiment, the resist film 32 may be formed on the absorber film 28. This aspect is shown in FIG. After a pattern is drawn and exposed on the resist film 32 by an electron beam drawing apparatus, a resist pattern can be formed through a development process. By performing dry etching on the absorber film 28 using this resist pattern as a mask, a pattern can be formed on the absorber film 28.
　保護膜１８上に形成された凹状の基準マーク２０を電子線描画装置によって容易に検出できるように、基準マーク２０の上方のレジスト膜３２を局所的に除去してもよい。除去の態様は、特に制限されない。また、例えば、基準マーク２０の上方のレジスト膜３２及び吸収体膜２８を除去してもよい。 The resist film 32 above the reference mark 20 may be locally removed so that the concave reference mark 20 formed on the protective film 18 can be easily detected by the electron beam lithography system. The mode of removal is not particularly limited. Also, for example, the resist film 32 and the absorber film 28 above the reference mark 20 may be removed.
　本実施形態の反射型マスクブランク３０において、吸収体膜２８とレジスト膜３２との間に、ハードマスク膜が形成されてもよい。ハードマスク膜は、吸収体膜２８をパターニングする際のマスクとして使用される。ハードマスク膜と吸収体膜２８は、エッチング選択性が互いに異なる材料によって形成される。吸収体膜２８の材料がタンタルあるいはタンタル化合物を含む場合、ハードマスク膜の材料は、クロム又はクロム化合物を含むことが好ましい。クロム化合物は、好ましくは、Ｃｒと、Ｎ、Ｏ、Ｃ、及びＨからなる群から選択される少なくとも一つを含む。 In the reflective mask blank 30 of the present embodiment, a hard mask film may be formed between the absorber film 28 and the resist film 32. The hard mask film is used as a mask when patterning the absorber film 28. The hard mask film and the absorber film 28 are formed of materials having different etching selectivity. When the material of the absorber film 28 contains tantalum or a tantalum compound, the material of the hard mask film preferably contains chromium or a chromium compound. The chromium compound preferably contains at least one selected from the group consisting of Cr and N, O, C, and H.
［反射型マスク］
　本実施形態の反射型マスクブランク３０を使用して、本実施形態の反射型マスク４０を製造することができる。以下、反射型マスク４０の製造方法について説明する。 [Reflective mask]
The reflective mask blank 30 of the present embodiment can be used to manufacture the reflective mask 40 of the present embodiment. Hereinafter, a method of manufacturing the reflective mask 40 will be described.
　図５は、反射型マスク４０の製造方法を示す模式図である。
　図５に示すように、まず、基板１２と、基板１２の上に形成された多層反射膜１４と、多層反射膜１４の上に形成された保護膜１８と、保護膜１８の上に形成された吸収体膜２８とを有する反射型マスクブランク３０を準備する（図５（ａ））。つぎに、吸収体膜２８の上に、レジスト膜３２を形成する（図５（ｂ））。レジスト膜３２に、電子線描画装置によってパターンを描画し、さらに現像・リンス工程を経ることによって、レジストパターン３２ａを形成する（図５（ｃ））。 FIG. 5 is a schematic view showing a method of manufacturing the reflective mask 40. As shown in FIG.
As shown in FIG. 5, first, the substrate 12, the multilayer reflective film 14 formed on the substrate 12, the protective film 18 formed on the multilayer reflective film 14, and the protective film 18 are formed. A reflective mask blank 30 having the absorber film 28 is prepared (FIG. 5A). Next, a resist film 32 is formed on the absorber film 28 (FIG. 5B). A pattern is drawn on the resist film 32 by an electron beam drawing apparatus, and a resist pattern 32a is formed by passing through a developing and rinsing process (FIG. 5C).
　レジストパターン３２ａをマスクとして、吸収体膜２８をドライエッチングする。これにより、吸収体膜２８のレジストパターン３２ａによって被覆されていない部分がエッチングされ、吸収体膜パターン２８ａが形成される（図５（ｄ））。 The absorber film 28 is dry etched using the resist pattern 32a as a mask. As a result, the portion of the absorber film 28 not covered by the resist pattern 32a is etched to form the absorber film pattern 28a (FIG. 5 (d)).
　なお、エッチングガスとしては、例えば、Ｃｌ２，ＳｉＣｌ４，ＣＨＣｌ３，ＣＣｌ４等の塩素系ガス、これら塩素系ガス及びＯ２を所定の割合で含む混合ガス、塩素系ガス及びＨｅを所定の割合で含む混合ガス、塩素系ガス及びＡｒを所定の割合で含む混合ガス、ＣＦ４，ＣＨＦ３，Ｃ２Ｆ６，Ｃ３Ｆ６，Ｃ４Ｆ６，Ｃ４Ｆ８，ＣＨ２Ｆ２，ＣＨ３Ｆ，Ｃ３Ｆ８，ＳＦ６，Ｆ等のフッ素系ガス、これらフッ素系ガス及びＯ２を所定の割合で含む混合ガス、フッ素系ガス及びＨｅを所定の割合で含む混合ガス、フッ素系ガス及びＡｒを所定の割合で含む混合ガス等を使用することができる。 In addition, as an etching gas, for example, chlorine based gases such as Cl 2 , SiCl 4 , CHCl 3 and CCl 4 , mixed gas containing these chlorine based gases and O 2 in a predetermined ratio, chlorine based gases and He as predetermined. A mixed gas containing a ratio, a chlorine-based gas and a mixed gas containing Ar at a predetermined ratio, CF 4 , CHF 3 , C 2 F 6 , C 3 F 6 , C 4 F 6 , C 4 F 8 , CH 2 F 2 Or a fluorine-based gas such as CH 3 F, C 3 F 8 , SF 6 or F, a mixed gas containing these fluorine-based gas and O 2 in a predetermined ratio, a mixed gas containing a fluorine-based gas and He in a predetermined ratio, A mixed gas containing fluorine-based gas and Ar at a predetermined ratio can be used.
　吸収体膜パターン２８ａが形成された後、例えば、レジスト剥離液によりレジストパターン３２ａを除去する。レジストパターン３２ａを除去した後、酸性やアルカリ性の水溶液を用いたウェット洗浄工程を経ることによって、本実施形態の反射型マスク４０が得られる（図５（ｅ））。 After the absorber film pattern 28a is formed, the resist pattern 32a is removed by, for example, a resist remover. After removing the resist pattern 32a, the reflective mask 40 of the present embodiment is obtained by passing through a wet cleaning process using an acidic or alkaline aqueous solution (FIG. 5E).
［半導体装置の製造方法］
　本実施形態の反射型マスク４０を使用したリソグラフィーにより、半導体基板上に転写パターンを形成することができる。この転写パターンは、反射型マスク４０の吸収体膜パターン２８ａが転写された形状を有している。半導体基板上に反射型マスク４０によって転写パターンを形成することによって、半導体装置を製造することができる。 [Method of Manufacturing Semiconductor Device]
A transfer pattern can be formed on a semiconductor substrate by lithography using the reflective mask 40 of the present embodiment. The transfer pattern has a shape in which the absorber film pattern 28 a of the reflective mask 40 is transferred. A semiconductor device can be manufactured by forming a transfer pattern on the semiconductor substrate using the reflective mask 40.
　図６を用いて、レジスト付き半導体基板５６にＥＵＶ光によってパターンを転写する方法について説明する。 A method of transferring a pattern to the resist-coated semiconductor substrate 56 by EUV light will be described with reference to FIG.
　図６は、パターン転写装置５０を示している。パターン転写装置５０は、レーザープラズマＸ線源５２、反射型マスク４０、及び、縮小光学系５４等を備えている。縮小光学系５４としては、Ｘ線反射ミラーが用いられている。 FIG. 6 shows a pattern transfer device 50. The pattern transfer apparatus 50 includes a laser plasma X-ray source 52, a reflective mask 40, a reduction optical system 54, and the like. As the reduction optical system 54, an X-ray reflection mirror is used.
　反射型マスク４０で反射されたパターンは、縮小光学系５４により、通常１／４程度に縮小される。例えば、露光波長として１３～１４ｎｍの波長帯を使用し、光路が真空中になるように予め設定する。このような条件で、レーザープラズマＸ線源５２で発生したＥＵＶ光を、反射型マスク４０に入射させる。反射型マスク４０によって反射された光を、縮小光学系５４を介して、レジスト付き半導体基板５６上に転写する。 The pattern reflected by the reflective mask 40 is usually reduced to about 1⁄4 by the reduction optical system 54. For example, a wavelength band of 13 to 14 nm is used as an exposure wavelength, and the light path is set in advance so as to be in vacuum. Under such conditions, EUV light generated by the laser plasma X-ray source 52 is made incident on the reflective mask 40. The light reflected by the reflective mask 40 is transferred onto the resisted semiconductor substrate 56 via the reduction optical system 54.
　反射型マスク４０に入射した光は、吸収体膜パターン２８ａのある部分では、吸収体膜に吸収されて反射されない。一方、吸収体膜パターン２８ａのない部分に入射した光は、多層反射膜１４により反射される。 The light incident on the reflective mask 40 is absorbed by the absorber film and not reflected at a portion where the absorber film pattern 28 a is present. On the other hand, the light incident on the portion without the absorber film pattern 28 a is reflected by the multilayer reflective film 14.
　反射型マスク４０によって反射された光は、縮小光学系５４に入射する。縮小光学系５４に入射した光は、レジスト付き半導体基板５６上のレジスト層に転写パターンを形成する。露光されたレジスト層を現像することによって、レジスト付き半導体基板５６上にレジストパターンを形成することができる。レジストパターンをマスクとして半導体基板５６をエッチングすることにより、半導体基板上に例えば所定の配線パターンを形成することができる。このような工程及びその他の必要な工程を経ることで、半導体装置が製造される。 The light reflected by the reflective mask 40 enters the reduction optical system 54. The light incident on the reduction optical system 54 forms a transfer pattern on the resist layer on the semiconductor substrate with resist 56. By developing the exposed resist layer, a resist pattern can be formed on the resist-coated semiconductor substrate 56. By etching the semiconductor substrate 56 using the resist pattern as a mask, for example, a predetermined wiring pattern can be formed on the semiconductor substrate. A semiconductor device is manufactured through such steps and other necessary steps.
　本実施形態の多層反射膜付き基板１０によれば、保護膜１８の表面に基準マーク２０が凹状に形成される。基準マーク２０の表層は、保護膜１８に含まれる元素のうち少なくとも１つの元素と同一の元素を含む。また、基準マーク２０の底部において、多層反射膜１４に含まれる複数の膜のうち少なくとも一部の膜が収縮したシュリンク領域２４が形成される。 According to the multilayer reflective film coated substrate 10 of the present embodiment, the reference mark 20 is formed in a concave shape on the surface of the protective film 18. The surface layer of the reference mark 20 contains an element identical to at least one element among the elements contained in the protective film 18. In addition, at the bottom of the reference mark 20, a shrink region 24 is formed in which at least a part of the plurality of films included in the multilayer reflective film 14 is contracted.
　本実施形態の多層反射膜付き基板１０によれば、基準マーク２０をレーザ加工する際に発生した塵によって、多層反射膜１４の表面が汚染されることを防止することができる。基準マーク２０の表層２２に、保護膜１８の少なくとも一部が残存しているためであると考えられる。 According to the multilayer reflective film coated substrate 10 of the present embodiment, it is possible to prevent the surface of the multilayer reflective film 14 from being contaminated by dust generated during laser processing of the reference mark 20. It is considered that at least a part of the protective film 18 remains on the surface layer 22 of the reference mark 20.
　本実施形態の多層反射膜付き基板１０によれば、基準マーク２０の表面に、多層反射膜１４の材料が露出することを防止することができる。したがって、洗浄耐性に優れた多層反射膜付き基板１０、反射型マスクブランク３０、及び反射型マスク４０を製造することができる。 According to the multilayer reflective film coated substrate 10 of the present embodiment, it is possible to prevent the material of the multilayer reflective film 14 from being exposed on the surface of the reference mark 20. Therefore, the multilayer reflective film coated substrate 10, the reflective mask blank 30, and the reflective mask 40 having excellent cleaning resistance can be manufactured.
　本実施形態の多層反射膜付き基板１０によれば、ＦＩＢ法を用いた場合よりも基準マークの加工に要する時間を短くすることが可能である。 According to the multilayer reflective film coated substrate 10 of the present embodiment, it is possible to shorten the time required to process the reference mark as compared to the case of using the FIB method.
　以下、本発明のさらに具体的な実施例について説明する。
（実施例１）
　ＳｉＯ２－ＴｉＯ２系のガラス基板（６インチ角、厚さが６．３５ｍｍ）を準備した。このガラス基板の端面を面取り加工、及び研削加工し、更に酸化セリウム砥粒を含む研磨液で粗研磨処理した。これらの処理を終えたガラス基板を両面研磨装置のキャリアにセットし、研磨液にコロイダルシリカ砥粒を含むアルカリ水溶液を用い、所定の研磨条件で精密研磨を行った。精密研磨終了後、ガラス基板に対し洗浄処理を行った。得られたガラス基板の主表面の表面粗さは、二乗平均平方根粗さ（ＲＭＳ）で、０．１０ｎｍ以下であった。得られたガラス基板の主表面の平坦度は、測定領域１３２ｍｍ×１３２ｍｍにおいて、３０ｎｍ以下であった。 Hereinafter, more specific examples of the present invention will be described.
Example 1
A SiO 2 -TiO 2 based glass substrate (6 inches square, 6.35 mm thick) was prepared. The end face of this glass substrate was chamfered and ground, and was roughly polished with a polishing solution containing cerium oxide abrasive grains. The glass substrate after these treatments was set on the carrier of the double-side polishing apparatus, and precision polishing was performed under predetermined polishing conditions using an alkaline aqueous solution containing colloidal silica abrasive grains as the polishing solution. After completion of the precision polishing, the glass substrate was subjected to a cleaning treatment. The surface roughness of the main surface of the obtained glass substrate was 0.10 nm or less in root mean square roughness (RMS). The flatness of the main surface of the obtained glass substrate was 30 nm or less in a measurement area of 132 mm × 132 mm.
　上記のガラス基板の裏面に、以下の条件で、ＣｒＮからなる裏面導電膜をマグネトロンスパッタリング法により形成した。
　（条件）：Ｃｒターゲット、Ａｒ＋Ｎ２ガス雰囲気（Ａｒ：Ｎ２＝９０％：１０％）、膜組成（Ｃｒ：９０原子％、Ｎ：１０原子％）、膜厚２０ｎｍ On the back surface of the above glass substrate, a back surface conductive film made of CrN was formed by magnetron sputtering under the following conditions.
(Conditions): Cr target, Ar + N 2 gas atmosphere (Ar: N 2 = 90%: 10%), film composition (Cr: 90 atomic%, N: 10 atomic%), film thickness 20 nm
　ガラス基板の裏面導電膜が形成された側と反対側の主表面上に、Ｍｏ膜／Ｓｉ膜を周期的に積層することで多層反射膜を形成した。 A multilayer reflective film was formed by periodically laminating an Mo film / Si film on the main surface of the glass substrate opposite to the side on which the back surface conductive film was formed.
　具体的には、ＭｏターゲットとＳｉターゲットを使用し、イオンビームスパッタリング（Ａｒを使用）により、基板上に、Ｍｏ膜及びＳｉ膜を交互に積層した。Ｍｏ膜の厚みは、２．８ｎｍである。Ｓｉ膜の厚みは、４．２ｎｍである。１周期のＭｏ／Ｓｉ膜の厚みは、７．０ｎｍである。このようなＭｏ／Ｓｉ膜を、４０周期積層し、最後にＳｉ膜を４．０ｎｍの膜厚で成膜し、多層反射膜を形成した。 Specifically, an Mo target and a Si target were used, and an Mo film and a Si film were alternately stacked on the substrate by ion beam sputtering (using Ar). The thickness of the Mo film is 2.8 nm. The thickness of the Si film is 4.2 nm. The thickness of one cycle of Mo / Si film is 7.0 nm. Such a Mo / Si film was laminated 40 cycles, and finally, a Si film was formed to a thickness of 4.0 nm to form a multilayer reflective film.
　多層反射膜の上に、Ｒｕ化合物を含む保護膜を形成した。具体的には、ＲｕＮｂターゲット（Ｒｕ：８０原子％、Ｎｂ：２０原子％）を使用し、Ａｒガス雰囲気にて、ＤＣマグネトロンスパッタリングにより、多層反射膜の上に、ＲｕＮｂ膜からなる保護膜を形成した。保護膜の厚みは、２．５ｎｍであった。 A protective film containing a Ru compound was formed on the multilayer reflective film. Specifically, a RuNb target (Ru: 80 at%, Nb: 20 at%) is used, and a protective film made of RuNb is formed on the multilayer reflective film by DC magnetron sputtering in an Ar gas atmosphere. did. The thickness of the protective film was 2.5 nm.
　保護膜の上に、レーザ加工によって、基準マークを形成した。
　レーザ加工の条件は、以下の通りであった。
　　レーザの種類：波長４０５ｎｍの半導体レーザ
　　レーザの出力：２０ｍＷ（連続波）
　　スポットサイズ：４３０ｎｍφ A reference mark was formed on the protective film by laser processing.
The conditions for laser processing were as follows.
Laser type: Semiconductor laser with a wavelength of 405 nm Laser output: 20 mW (continuous wave)
Spot size: 430 nmφ
　基準マークの形状及び寸法は、以下の通りであった。
　　形状：略十字型
　　深さＤ：４０ｎｍ
　　幅Ｗ：２μｍ
　　長さＬ：１ｍｍ
　　傾斜角θ：５．７度 The shape and dimensions of the fiducial marks were as follows.
Shape: approximately cruciform depth D: 40 nm
Width W: 2 μm
Length L: 1 mm
Inclination angle θ: 5.7 degrees
　基準マークの断面を、透過型電子顕微鏡（ＴＥＭ）によって撮影した。撮影によって得られた画像を、図７に示す。図７を見れば分かる通り、凹状の基準マークの底部には、多層反射膜に含まれる複数の膜のうち少なくとも一部の膜が収縮したシュリンク領域が形成されていた。また、基準マークの底部の中央部付近であって、シュリンク領域の上方には、多層反射膜に含まれる複数の膜のうち少なくとも一部の膜が互いに一体化したミキシング領域が形成されていた。シュリンク領域では、多層反射膜に含まれる１周期のＭｏ／Ｓｉ膜の厚みが、７．０ｎｍから６．０ｎｍに減少していた。ミキシング領域の厚さは、１２０ｎｍであった。 Cross sections of the fiducial marks were taken by transmission electron microscopy (TEM). An image obtained by photographing is shown in FIG. As can be seen from FIG. 7, at the bottom of the concave reference mark, a shrink region in which at least a part of the plurality of films included in the multilayer reflective film is shrunk is formed. Further, in the vicinity of the central portion of the bottom portion of the reference mark and above the shrink region, there is formed a mixing region in which at least a part of the plurality of films included in the multilayer reflective film are integrated. In the shrink region, the thickness of one cycle of Mo / Si film included in the multilayer reflective film decreased from 7.0 nm to 6.0 nm. The thickness of the mixing area was 120 nm.
　基準マークの表層を、ＥＤＸ（エネルギー分散型Ｘ線分析）によって分析した。その結果、基準マークのシュリンク領域の表層には、保護膜に含まれている元素と同一の元素である、Ｒｕ及びＮｂが含まれていた。また、酸素（Ｏ）も検出されたため、基準マークの表層には、ＲｕＮｂＯが含まれていると考えられる。また、基準マークのミキシング領域の表層には、Ｒｕ、Ｎｂ、Ｓｉ、Ｍｏ、及びＯが含まれていたため、ＲｕＮｂＯ、ＲｕＳｉ又はＭｏＳｉ等が含まれていると考えられる。 The surface of the fiducial marks was analyzed by EDX (energy dispersive x-ray analysis). As a result, the surface layer of the shrink region of the reference mark contained Ru and Nb which are the same elements as the elements contained in the protective film. In addition, since oxygen (O) was also detected, it is considered that RuNbO is contained in the surface layer of the reference mark. Moreover, since Ru, Nb, Si, Mo and O were contained in the surface layer of the mixing area of the reference mark, it is considered that RuNbO, RuSi, MoSi or the like is contained.
　欠陥検査装置（レーザーテック株式会社製、ABI）を用いて、多層反射膜付き基板の欠陥検査を行った。欠陥検査では、保護膜の上に凹状に形成された基準マークを基準として、欠陥の位置を特定した。その結果、欠陥の個数は、従来のＦＩＢ法によって基準マークを形成した場合よりも、減少していた。 Defect inspection of the multilayer reflective film coated substrate was performed using a defect inspection apparatus (ABI manufactured by Lasertec Corporation). In defect inspection, the position of a defect was specified on the basis of a fiducial mark formed concavely on the protective film. As a result, the number of defects was reduced compared to the case where the fiducial marks were formed by the conventional FIB method.
　多層反射膜付き基板の保護膜の上に吸収体膜を形成し、反射型マスクブランクを製造した。具体的には、ＴａＢＮ（厚み５６ｎｍ）とＴａＢＯ（厚み１４ｎｍ）の積層膜からなる吸収体膜を、ＤＣマグネトロンスパッタリングにより形成した。ＴａＢＮ膜は、ＴａＢターゲットを使用し、ＡｒガスとＮ２ガスの混合ガス雰囲気における反応性スパッタリングにより形成した。ＴａＢＯ膜は、ＴａＢターゲットを使用し、ＡｒガスとＯ２ガスの混合ガス雰囲気における反応性スパッタリングにより形成した。 An absorber film was formed on the protective film of the multilayer reflective film coated substrate to manufacture a reflective mask blank. Specifically, an absorber film made of a laminated film of TaBN (56 nm in thickness) and TaBO (14 nm in thickness) was formed by DC magnetron sputtering. The TaBN film was formed by reactive sputtering in a mixed gas atmosphere of Ar gas and N 2 gas using a TaB target. The TaBO film was formed by reactive sputtering in a mixed gas atmosphere of Ar gas and O 2 gas using a TaB target.
　吸収体膜に転写された凹状の基準マークを、電子線描画装置によって検出した。その結果、基準マークを検出可能であり、吸収体膜に転写された基準マークが、電子線描画装置によって検出可能な程度に十分なコントラストを有していることを確認することができた。 The concave reference mark transferred to the absorber film was detected by an electron beam writing apparatus. As a result, it was possible to detect that the reference mark was detectable, and it was possible to confirm that the reference mark transferred to the absorber film had a contrast sufficient to be detectable by the electron beam lithography system.
　欠陥検査装置（レーザーテック株式会社製、M8350）を用いて、吸収体膜上の欠陥検査を行った。欠陥検査では、吸収体膜の上に凹状に転写された基準マークを基準として、欠陥の位置を特定した。その結果、欠陥の個数は、従来のＦＩＢ法によって基準マークを形成した場合よりも、減少していた。 Defect inspection on the absorber film was performed using a defect inspection apparatus (M8350 manufactured by Lasertec Corporation). In the defect inspection, the position of the defect was specified on the basis of the fiducial mark transferred concavely on the absorber film. As a result, the number of defects was reduced compared to the case where the fiducial marks were formed by the conventional FIB method.
　上記で製造した反射型マスクブランクの吸収体膜上に、レジスト膜を形成した。電子線描画装置を用いて、欠陥検査によって得られた欠陥情報に基づいてレジスト膜にパターンを描画した。パターンを描画した後、所定の現像処理を行い、吸収体膜上にレジストパターンを形成した。 A resist film was formed on the absorber film of the reflective mask blank manufactured above. A pattern was drawn on a resist film based on defect information obtained by defect inspection using an electron beam drawing apparatus. After drawing the pattern, predetermined development processing was performed to form a resist pattern on the absorber film.
　レジストパターンをマスクとして、吸収体膜にパターンを形成した。具体的には、フッ素系ガス（ＣＦ４ガス）により、上層のＴａＢＯ膜をドライエッチングした後、塩素系ガス（Ｃｌ２ガス）により、下層のＴａＢＮ膜をドライエッチングした。 Using the resist pattern as a mask, a pattern was formed on the absorber film. Specifically, the upper TaBO film was dry etched with a fluorine-based gas (CF 4 gas), and then the lower TaBN film was dry etched with a chlorine-based gas (Cl 2 gas).
　吸収体膜パターン上に残ったレジストパターンを、熱硫酸で除去することで、実施例１に係る反射型マスクが得られた。こうして得られた反射型マスクを露光装置にセットし、レジスト膜を形成した半導体基板上へのパターン転写を行う場合、反射型マスク起因の転写パターンの欠陥も無く、良好なパターン転写を行うことができる。 The reflective mask according to Example 1 was obtained by removing the resist pattern remaining on the absorber film pattern with hot sulfuric acid. When the thus obtained reflective mask is set in an exposure apparatus and pattern transfer is performed on a semiconductor substrate on which a resist film is formed, good pattern transfer can be performed without defects in the transfer pattern caused by the reflective mask. it can.
（実施例２）
　ＳｉＯ２－ＴｉＯ２系のガラス基板（６インチ角、厚さが６．３５ｍｍ）を準備した。このガラス基板の端面を面取り加工、及び研削加工し、更に酸化セリウム砥粒を含む研磨液で粗研磨処理した。これらの処理を終えたガラス基板を両面研磨装置のキャリアにセットし、研磨液にコロイダルシリカ砥粒を含むアルカリ水溶液を用い、所定の研磨条件で精密研磨を行った。精密研磨終了後、ガラス基板に対し洗浄処理を行った。得られたガラス基板の主表面の表面粗さは、二乗平均平方根粗さ（ＲＭＳ）で、０．１０ｎｍ以下であった。得られたガラス基板の主表面の平坦度は、測定領域１３２ｍｍ×１３２ｍｍにおいて、３０ｎｍ以下であった。 (Example 2)
A SiO 2 -TiO 2 based glass substrate (6 inches square, 6.35 mm thick) was prepared. The end face of this glass substrate was chamfered and ground, and was roughly polished with a polishing solution containing cerium oxide abrasive grains. The glass substrate after these treatments was set on the carrier of the double-side polishing apparatus, and precision polishing was performed under predetermined polishing conditions using an alkaline aqueous solution containing colloidal silica abrasive grains as the polishing solution. After completion of the precision polishing, the glass substrate was subjected to a cleaning treatment. The surface roughness of the main surface of the obtained glass substrate was 0.10 nm or less in root mean square roughness (RMS). The flatness of the main surface of the obtained glass substrate was 30 nm or less in a measurement area of 132 mm × 132 mm.
　上記のガラス基板の裏面に、以下の条件で、ＣｒＮからなる裏面導電膜をマグネトロンスパッタリング法により形成した。
　（条件）：Ｃｒターゲット、Ａｒ＋Ｎ２ガス雰囲気（Ａｒ：Ｎ２＝９０％：１０％）、膜組成（Ｃｒ：９０原子％、Ｎ：１０原子％）、膜厚２０ｎｍ On the back surface of the above glass substrate, a back surface conductive film made of CrN was formed by magnetron sputtering under the following conditions.
(Conditions): Cr target, Ar + N 2 gas atmosphere (Ar: N 2 = 90%: 10%), film composition (Cr: 90 atomic%, N: 10 atomic%), film thickness 20 nm
　ガラス基板の裏面導電膜が形成された側と反対側の主表面上に、Ｍｏ膜／Ｓｉ膜を周期的に積層することで多層反射膜を形成した。 A multilayer reflective film was formed by periodically laminating an Mo film / Si film on the main surface of the glass substrate opposite to the side on which the back surface conductive film was formed.
　具体的には、ＭｏターゲットとＳｉターゲットを使用し、イオンビームスパッタリング（Ａｒを使用）により、基板上に、Ｍｏ膜及びＳｉ膜を交互に積層した。Ｍｏ膜の厚みは、２．８ｎｍである。Ｓｉ膜の厚みは、４．２ｎｍである。１周期のＭｏ／Ｓｉ膜の厚みは、７．０ｎｍである。このようなＭｏ／Ｓｉ膜を、４０周期積層し、最後にＳｉ膜を４．０ｎｍの膜厚で成膜し、多層反射膜を形成した。 Specifically, an Mo target and a Si target were used, and an Mo film and a Si film were alternately stacked on the substrate by ion beam sputtering (using Ar). The thickness of the Mo film is 2.8 nm. The thickness of the Si film is 4.2 nm. The thickness of one cycle of Mo / Si film is 7.0 nm. Such a Mo / Si film was laminated 40 cycles, and finally, a Si film was formed to a thickness of 4.0 nm to form a multilayer reflective film.
　多層反射膜の上に、Ｒｕを含む保護膜を形成した。具体的には、Ｒｕターゲットを使用し、Ａｒガス雰囲気にて、ＤＣマグネトロンスパッタリングにより、多層反射膜の上に、Ｒｕ膜からなる保護膜を形成した。保護膜の厚みは、２．５ｎｍであった。 A protective film containing Ru was formed on the multilayer reflective film. Specifically, a Ru target was used, and a protective film made of a Ru film was formed on the multilayer reflective film by DC magnetron sputtering in an Ar gas atmosphere. The thickness of the protective film was 2.5 nm.
　保護膜の上に、レーザ加工によって、基準マークを形成した。
　レーザ加工の条件は、以下の通りであった。
　　レーザの種類：波長４０５ｎｍの半導体レーザ
　　レーザの出力：２０ｍＷ（連続波）
　　スポットサイズ：４３０ｎｍφ A reference mark was formed on the protective film by laser processing.
The conditions for laser processing were as follows.
Laser type: Semiconductor laser with a wavelength of 405 nm Laser output: 20 mW (continuous wave)
Spot size: 430 nmφ
　基準マークの形状及び寸法は、以下の通りであった。
　　形状：略十字型
　　深さＤ：４０ｎｍ
　　幅Ｗ：２μｍ
　　長さＬ：１ｍｍ
　　傾斜角θ：５．７度 The shape and dimensions of the fiducial marks were as follows.
Shape: approximately cruciform depth D: 40 nm
Width W: 2 μm
Length L: 1 mm
Inclination angle θ: 5.7 degrees
　基準マークの断面を、透過型電子顕微鏡（ＴＥＭ）によって撮影した。その結果、凹状の基準マークの底部には、多層反射膜に含まれる複数の膜のうち少なくとも一部の膜が収縮したシュリンク領域が形成されていた。また、基準マークの底部の中央部付近であって、シュリンク領域の上方には、多層反射膜に含まれる複数の膜のうち少なくとも一部の膜が互いに一体化したミキシング領域が形成されていた。シュリンク領域では、多層反射膜に含まれる１周期のＭｏ／Ｓｉ膜の厚みが、７．０ｎｍから６．０ｎｍに減少していた。ミキシング領域の厚さは、１２０ｎｍであった。 Cross sections of the fiducial marks were taken by transmission electron microscopy (TEM). As a result, at the bottom of the concave reference mark, a shrink region in which at least a part of the plurality of films included in the multilayer reflective film is shrunk is formed. Further, in the vicinity of the central portion of the bottom portion of the reference mark and above the shrink region, there is formed a mixing region in which at least a part of the plurality of films included in the multilayer reflective film are integrated. In the shrink region, the thickness of one cycle of Mo / Si film included in the multilayer reflective film decreased from 7.0 nm to 6.0 nm. The thickness of the mixing area was 120 nm.
　基準マークの表層を、ＥＤＸ（エネルギー分散型Ｘ線分析）によって分析した。その結果、基準マークのシュリンク領域の表層には、保護膜に含まれている元素と同一の元素である、Ｒｕが含まれていた。また、酸素（Ｏ）も検出されたため、基準マークの表層にはＲｕＯが含まれていると考えられる。また、基準マークのミキシング領域の表層には、Ｒｕ、Ｓｉ、Ｍｏ、及びＯが含まれていたため、ＲｕＯ、ＲｕＳｉ又はＭｏＳｉ等が含まれていると考えられる。 The surface of the fiducial marks was analyzed by EDX (energy dispersive x-ray analysis). As a result, the surface layer of the shrink region of the reference mark contained Ru, which is the same element as the element contained in the protective film. In addition, since oxygen (O) was also detected, it is considered that RuO is contained in the surface layer of the reference mark. Moreover, since Ru, Si, Mo, and O were contained in the surface layer of the mixing area | region of a reference mark, it is thought that RuO, RuSi, MoSi, etc. are contained.
　欠陥検査装置（レーザーテック株式会社製、ABI）を用いて、多層反射膜付き基板の欠陥検査を行った。欠陥検査では、保護膜の上に凹状に形成された基準マークを基準として、欠陥の位置を特定した。その結果、欠陥の個数は、従来のＦＩＢ法によって基準マークを形成した場合よりも、減少していた。 Defect inspection of the multilayer reflective film coated substrate was performed using a defect inspection apparatus (ABI manufactured by Lasertec Corporation). In defect inspection, the position of a defect was specified on the basis of a fiducial mark formed concavely on the protective film. As a result, the number of defects was reduced compared to the case where the fiducial marks were formed by the conventional FIB method.
　多層反射膜付き基板の保護膜の上に吸収体膜を形成し、反射型マスクブランクを製造した。具体的には、ＴａＢＮ（厚み５６ｎｍ）とＴａＢＯ（厚み１４ｎｍ）の積層膜からなる吸収体膜を、ＤＣマグネトロンスパッタリングにより形成した。ＴａＢＮ膜は、ＴａＢターゲットを使用し、ＡｒガスとＮ２ガスの混合ガス雰囲気における反応性スパッタリングにより形成した。ＴａＢＯ膜は、ＴａＢターゲットを使用し、ＡｒガスとＯ２ガスの混合ガス雰囲気における反応性スパッタリングにより形成した。 An absorber film was formed on the protective film of the multilayer reflective film coated substrate to manufacture a reflective mask blank. Specifically, an absorber film made of a laminated film of TaBN (56 nm in thickness) and TaBO (14 nm in thickness) was formed by DC magnetron sputtering. The TaBN film was formed by reactive sputtering in a mixed gas atmosphere of Ar gas and N 2 gas using a TaB target. The TaBO film was formed by reactive sputtering in a mixed gas atmosphere of Ar gas and O 2 gas using a TaB target.
　吸収体膜に転写された凹状の基準マークを、電子線描画装置によって検出した。その結果、基準マークを検出可能であり、吸収体膜に転写された基準マークが、電子線描画装置によって検出可能な程度に十分なコントラストを有していることを確認することができた。 The concave reference mark transferred to the absorber film was detected by an electron beam writing apparatus. As a result, it was possible to detect that the reference mark was detectable, and it was possible to confirm that the reference mark transferred to the absorber film had a contrast sufficient to be detectable by the electron beam lithography system.
　欠陥検査装置（レーザーテック株式会社製、M8350）を用いて、吸収体膜上の欠陥検査を行った。欠陥検査では、吸収体膜の上に凹状に転写された基準マークを基準として、欠陥の位置を特定した。その結果、欠陥の個数は、従来のＦＩＢによって基準マークを形成した場合よりも、減少していた。 Defect inspection on the absorber film was performed using a defect inspection apparatus (M8350 manufactured by Lasertec Corporation). In the defect inspection, the position of the defect was specified on the basis of the fiducial mark transferred concavely on the absorber film. As a result, the number of defects was reduced compared to the case where the fiducial marks were formed by the conventional FIB.
　上記で製造した反射型マスクブランクの吸収体膜上に、レジスト膜を形成した。電子線描画装置を用いて、欠陥検査によって得られた欠陥情報に基づいてレジスト膜にパターンを描画した。パターンを描画した後、所定の現像処理を行い、吸収体膜上にレジストパターンを形成した。 A resist film was formed on the absorber film of the reflective mask blank manufactured above. A pattern was drawn on a resist film based on defect information obtained by defect inspection using an electron beam drawing apparatus. After drawing the pattern, predetermined development processing was performed to form a resist pattern on the absorber film.
　レジストパターンをマスクとして、吸収体膜にパターンを形成した。具体的には、フッ素系ガス（ＣＦ４ガス）により、上層のＴａＢＯ膜をドライエッチングした後、塩素系ガス（Ｃｌ２ガス）により、下層のＴａＢＮ膜をドライエッチングした。 Using the resist pattern as a mask, a pattern was formed on the absorber film. Specifically, the upper TaBO film was dry etched with a fluorine-based gas (CF 4 gas), and then the lower TaBN film was dry etched with a chlorine-based gas (Cl 2 gas).
　吸収体膜パターン上に残ったレジストパターンを、熱硫酸で除去することで、実施例２に係る反射型マスクが得られた。こうして得られた反射型マスクを露光装置にセットし、レジスト膜を形成した半導体基板上へのパターン転写を行う場合、反射型マスク起因の転写パターンの欠陥も無く、良好なパターン転写を行うことができる。 The resist pattern remaining on the absorber film pattern was removed with hot sulfuric acid to obtain a reflective mask according to Example 2. When the thus obtained reflective mask is set in an exposure apparatus and pattern transfer is performed on a semiconductor substrate on which a resist film is formed, good pattern transfer can be performed without defects in the transfer pattern caused by the reflective mask. it can.
（実施例３）
　ＳｉＯ２－ＴｉＯ２系のガラス基板（６インチ角、厚さが６．３５ｍｍ）を準備した。このガラス基板の端面を面取り加工、及び研削加工し、更に酸化セリウム砥粒を含む研磨液で粗研磨処理した。これらの処理を終えたガラス基板を両面研磨装置のキャリアにセットし、研磨液にコロイダルシリカ砥粒を含むアルカリ水溶液を用い、所定の研磨条件で精密研磨を行った。精密研磨終了後、ガラス基板に対し洗浄処理を行った。得られたガラス基板の主表面の表面粗さは、二乗平均平方根粗さ（ＲＭＳ）で、０．１０ｎｍ以下であった。得られたガラス基板の主表面の平坦度は、測定領域１３２ｍｍ×１３２ｍｍにおいて、３０ｎｍ以下であった。 (Example 3)
A SiO 2 -TiO 2 based glass substrate (6 inches square, 6.35 mm thick) was prepared. The end face of this glass substrate was chamfered and ground, and was roughly polished with a polishing solution containing cerium oxide abrasive grains. The glass substrate after these treatments was set on the carrier of the double-side polishing apparatus, and precision polishing was performed under predetermined polishing conditions using an alkaline aqueous solution containing colloidal silica abrasive grains as the polishing solution. After completion of the precision polishing, the glass substrate was subjected to a cleaning treatment. The surface roughness of the main surface of the obtained glass substrate was 0.10 nm or less in root mean square roughness (RMS). The flatness of the main surface of the obtained glass substrate was 30 nm or less in a measurement area of 132 mm × 132 mm.
　上記のガラス基板の裏面に、以下の条件で、ＣｒＮからなる裏面導電膜をマグネトロンスパッタリング法により形成した。
　（条件）：Ｃｒターゲット、Ａｒ＋Ｎ２ガス雰囲気（Ａｒ：Ｎ２＝９０％：１０％）、膜組成（Ｃｒ：９０原子％、Ｎ：１０原子％）、膜厚２０ｎｍ On the back surface of the above glass substrate, a back surface conductive film made of CrN was formed by magnetron sputtering under the following conditions.
(Conditions): Cr target, Ar + N 2 gas atmosphere (Ar: N 2 = 90%: 10%), film composition (Cr: 90 atomic%, N: 10 atomic%), film thickness 20 nm
　ガラス基板の裏面導電膜が形成された側と反対側の主表面上に、Ｍｏ膜／Ｓｉ膜を周期的に積層することで多層反射膜を形成した。 A multilayer reflective film was formed by periodically laminating an Mo film / Si film on the main surface of the glass substrate opposite to the side on which the back surface conductive film was formed.
　具体的には、ＭｏターゲットとＳｉターゲットを使用し、イオンビームスパッタリング（Ａｒを使用）により、基板上に、Ｍｏ膜及びＳｉ膜を交互に積層した。Ｍｏ膜の厚みは、２．８ｎｍである。Ｓｉ膜の厚みは、４．２ｎｍである。１周期のＭｏ／Ｓｉ膜の厚みは、７．０ｎｍである。このようなＭｏ／Ｓｉ膜を、４０周期積層し、最後にＳｉ膜を４．０ｎｍの膜厚で成膜し、多層反射膜を形成した。 Specifically, an Mo target and a Si target were used, and an Mo film and a Si film were alternately stacked on the substrate by ion beam sputtering (using Ar). The thickness of the Mo film is 2.8 nm. The thickness of the Si film is 4.2 nm. The thickness of one cycle of Mo / Si film is 7.0 nm. Such a Mo / Si film was laminated 40 cycles, and finally, a Si film was formed to a thickness of 4.0 nm to form a multilayer reflective film.
　多層反射膜の上に、Ｒｕ化合物を含む保護膜を形成した。具体的には、ＲｕＮｂターゲット（Ｒｕ：８０原子％、Ｎｂ：２０原子％）を使用し、Ａｒガス雰囲気にて、ＤＣマグネトロンスパッタリングにより、多層反射膜の上に、ＲｕＮｂ膜からなる保護膜を形成した。保護膜の厚みは、２．５ｎｍであった。 A protective film containing a Ru compound was formed on the multilayer reflective film. Specifically, a RuNb target (Ru: 80 at%, Nb: 20 at%) is used, and a protective film made of RuNb is formed on the multilayer reflective film by DC magnetron sputtering in an Ar gas atmosphere. did. The thickness of the protective film was 2.5 nm.
　保護膜の上に、レーザ加工によって、基準マークを形成した。
　レーザ加工の条件は、以下の通りであった。
　　レーザの種類：波長４０５ｎｍの半導体レーザ
　　レーザの出力：１０ｍＷ（連続波）
　　スポットサイズ：４３０ｎｍφ A reference mark was formed on the protective film by laser processing.
The conditions for laser processing were as follows.
Laser type: Semiconductor laser with a wavelength of 405 nm Laser output: 10 mW (continuous wave)
Spot size: 430 nmφ
　基準マークの形状及び寸法は、以下の通りであった。
　　形状：略十字型
　　深さＤ：３８ｎｍ
　　幅Ｗ：２μｍ
　　長さＬ：１ｍｍ
　　傾斜角θ：３．６度 The shape and dimensions of the fiducial marks were as follows.
Shape: approximately cruciform depth D: 38 nm
Width W: 2 μm
Length L: 1 mm
Inclination angle θ: 3.6 degrees
　基準マークの表層を、ＥＤＸ（エネルギー分散型Ｘ線分析）によって分析した。その結果、基準マークの表層には、保護膜に含まれている元素と同一の元素である、Ｒｕ及びＮｂが含まれていた。 The surface of the fiducial marks was analyzed by EDX (energy dispersive x-ray analysis). As a result, the surface layer of the reference mark contained Ru and Nb, which are the same elements as the elements contained in the protective film.
　基準マークの断面を、透過型電子顕微鏡（ＴＥＭ）によって撮影した。その結果、凹状の基準マークの底部には、多層反射膜に含まれる複数の膜のうち少なくとも一部の膜が収縮したシュリンク領域が形成されていた。しかし、実施例１及び実施例２とは異なり、シュリンク領域の上方には、ミキシング領域が形成されていなかった。シュリンク領域では、多層反射膜に含まれる１周期のＭｏ／Ｓｉ膜の厚みが、７．０ｎｍから６．２ｎｍに減少していた。 Cross sections of the fiducial marks were taken by transmission electron microscopy (TEM). As a result, at the bottom of the concave reference mark, a shrink region in which at least a part of the plurality of films included in the multilayer reflective film is shrunk is formed. However, unlike Example 1 and Example 2, the mixing area was not formed above the shrink area. In the shrink region, the thickness of one cycle of Mo / Si film included in the multilayer reflective film decreased from 7.0 nm to 6.2 nm.
　欠陥検査装置（レーザーテック株式会社製、ABI）を用いて、多層反射膜付き基板の欠陥検査を行った。欠陥検査では、保護膜の上に凹状に形成された基準マークを基準として、欠陥の位置を特定した。その結果、欠陥の個数は、従来のＦＩＢ法によって基準マークを形成した場合よりも、減少していた。 Defect inspection of the multilayer reflective film coated substrate was performed using a defect inspection apparatus (ABI manufactured by Lasertec Corporation). In defect inspection, the position of a defect was specified on the basis of a fiducial mark formed concavely on the protective film. As a result, the number of defects was reduced compared to the case where the fiducial marks were formed by the conventional FIB method.
　多層反射膜付き基板の保護膜の上に吸収体膜を形成し、反射型マスクブランクを製造した。具体的には、ＴａＢＮ（厚み５６ｎｍ）とＴａＢＯ（厚み１４ｎｍ）の積層膜からなる吸収体膜を、ＤＣマグネトロンスパッタリングにより形成した。ＴａＢＮ膜は、ＴａＢターゲットを使用し、ＡｒガスとＮ２ガスの混合ガス雰囲気における反応性スパッタリングにより形成した。ＴａＢＯ膜は、ＴａＢターゲットを使用し、ＡｒガスとＯ２ガスの混合ガス雰囲気における反応性スパッタリングにより形成した。 An absorber film was formed on the protective film of the multilayer reflective film coated substrate to manufacture a reflective mask blank. Specifically, an absorber film made of a laminated film of TaBN (56 nm in thickness) and TaBO (14 nm in thickness) was formed by DC magnetron sputtering. The TaBN film was formed by reactive sputtering in a mixed gas atmosphere of Ar gas and N 2 gas using a TaB target. The TaBO film was formed by reactive sputtering in a mixed gas atmosphere of Ar gas and O 2 gas using a TaB target.
　吸収体膜に転写された凹状の基準マークを、電子線描画装置によって検出した。その結果、基準マークを検出可能であり、吸収体膜に転写された基準マークが、電子線描画装置によって検出可能な程度に十分なコントラストを有していることを確認することができた。 The concave reference mark transferred to the absorber film was detected by an electron beam writing apparatus. As a result, it was possible to detect that the reference mark was detectable, and it was possible to confirm that the reference mark transferred to the absorber film had a contrast sufficient to be detectable by the electron beam lithography system.
　欠陥検査装置（レーザーテック株式会社製、M8350）を用いて、吸収体膜上の欠陥検査を行った。欠陥検査では、吸収体膜の上に凹状に転写された基準マークを基準として、欠陥の位置を特定した。その結果、欠陥の個数は、従来のＦＩＢ法によって基準マークを形成した場合よりも、減少していた。 Defect inspection on the absorber film was performed using a defect inspection apparatus (M8350 manufactured by Lasertec Corporation). In the defect inspection, the position of the defect was specified on the basis of the fiducial mark transferred concavely on the absorber film. As a result, the number of defects was reduced compared to the case where the fiducial marks were formed by the conventional FIB method.
　上記で製造した反射型マスクブランクの吸収体膜上に、レジスト膜を形成した。電子線描画装置を用いて、欠陥検査によって得られた欠陥情報に基づいてレジスト膜にパターンを描画した。パターンを描画した後、所定の現像処理を行い、吸収体膜上にレジストパターンを形成した。 A resist film was formed on the absorber film of the reflective mask blank manufactured above. A pattern was drawn on a resist film based on defect information obtained by defect inspection using an electron beam drawing apparatus. After drawing the pattern, predetermined development processing was performed to form a resist pattern on the absorber film.
　レジストパターンをマスクとして、吸収体膜にパターンを形成した。具体的には、フッ素系ガス（ＣＦ４ガス）により、上層のＴａＢＯ膜をドライエッチングした後、塩素系ガス（Ｃｌ２ガス）により、下層のＴａＢＮ膜をドライエッチングした。 Using the resist pattern as a mask, a pattern was formed on the absorber film. Specifically, the upper TaBO film was dry etched with a fluorine-based gas (CF 4 gas), and then the lower TaBN film was dry etched with a chlorine-based gas (Cl 2 gas).
　吸収体膜パターン上に残ったレジストパターンを、熱硫酸で除去することで、実施例３に係る反射型マスクが得られた。こうして得られた反射型マスクを露光装置にセットし、レジスト膜を形成した半導体基板上へのパターン転写を行う場合、反射型マスク起因の転写パターンの欠陥も無く、良好なパターン転写を行うことができる。 The resist pattern remaining on the absorber film pattern was removed with hot sulfuric acid to obtain a reflective mask according to Example 3. When the thus obtained reflective mask is set in an exposure apparatus and pattern transfer is performed on a semiconductor substrate on which a resist film is formed, good pattern transfer can be performed without defects in the transfer pattern caused by the reflective mask. it can.
（比較例１）
　ＳｉＯ２－ＴｉＯ２系のガラス基板（６インチ角、厚さが６．３５ｍｍ）を準備した。このガラス基板の端面を面取り加工、及び研削加工し、更に酸化セリウム砥粒を含む研磨液で粗研磨処理した。これらの処理を終えたガラス基板を両面研磨装置のキャリアにセットし、研磨液にコロイダルシリカ砥粒を含むアルカリ水溶液を用い、所定の研磨条件で精密研磨を行った。精密研磨終了後、ガラス基板に対し洗浄処理を行った。得られたガラス基板の主表面の表面粗さは、二乗平均平方根粗さ（ＲＭＳ）で、０．１０ｎｍ以下であった。得られたガラス基板の主表面の平坦度は、測定領域１３２ｍｍ×１３２ｍｍにおいて、３０ｎｍ以下であった。 (Comparative example 1)
A SiO 2 -TiO 2 based glass substrate (6 inches square, 6.35 mm thick) was prepared. The end face of this glass substrate was chamfered and ground, and was roughly polished with a polishing solution containing cerium oxide abrasive grains. The glass substrate after these treatments was set on the carrier of the double-side polishing apparatus, and precision polishing was performed under predetermined polishing conditions using an alkaline aqueous solution containing colloidal silica abrasive grains as the polishing solution. After completion of the precision polishing, the glass substrate was subjected to a cleaning treatment. The surface roughness of the main surface of the obtained glass substrate was 0.10 nm or less in root mean square roughness (RMS). The flatness of the main surface of the obtained glass substrate was 30 nm or less in a measurement area of 132 mm × 132 mm.
　上記のガラス基板の裏面に、以下の条件で、ＣｒＮからなる裏面導電膜をマグネトロンスパッタリング法により形成した。
　（条件）：Ｃｒターゲット、Ａｒ＋Ｎ２ガス雰囲気（Ａｒ：Ｎ２＝９０％：１０％）、膜組成（Ｃｒ：９０原子％、Ｎ：１０原子％）、膜厚２０ｎｍ On the back surface of the above glass substrate, a back surface conductive film made of CrN was formed by magnetron sputtering under the following conditions.
(Conditions): Cr target, Ar + N 2 gas atmosphere (Ar: N 2 = 90%: 10%), film composition (Cr: 90 atomic%, N: 10 atomic%), film thickness 20 nm
　ガラス基板の裏面導電膜が形成された側と反対側の主表面上に、Ｍｏ膜／Ｓｉ膜を周期的に積層することで多層反射膜を形成した。 A multilayer reflective film was formed by periodically laminating an Mo film / Si film on the main surface of the glass substrate opposite to the side on which the back surface conductive film was formed.
　具体的には、ＭｏターゲットとＳｉターゲットを使用し、イオンビームスパッタリング（Ａｒを使用）により、基板上に、Ｍｏ膜及びＳｉ膜を交互に積層した。Ｍｏ膜の厚みは、２．８ｎｍである。Ｓｉ膜の厚みは、４．２ｎｍである。１周期のＭｏ／Ｓｉ膜の厚みは、７．０ｎｍである。このようなＭｏ／Ｓｉ膜を、４０周期積層し、最後にＳｉ膜を４．０ｎｍの膜厚で成膜し、多層反射膜を形成した。 Specifically, an Mo target and a Si target were used, and an Mo film and a Si film were alternately stacked on the substrate by ion beam sputtering (using Ar). The thickness of the Mo film is 2.8 nm. The thickness of the Si film is 4.2 nm. The thickness of one cycle of Mo / Si film is 7.0 nm. Such a Mo / Si film was laminated 40 cycles, and finally, a Si film was formed to a thickness of 4.0 nm to form a multilayer reflective film.
　多層反射膜の上に、Ｒｕ化合物を含む保護膜を形成した。具体的には、ＲｕＮｂターゲット（Ｒｕ：８０原子％、Ｎｂ：２０原子％）を使用し、Ａｒガス雰囲気にて、ＤＣマグネトロンスパッタリングにより、多層反射膜の上に、ＲｕＮｂ膜からなる保護膜を形成した。保護膜の厚みは、２．５ｎｍであった。 A protective film containing a Ru compound was formed on the multilayer reflective film. Specifically, a RuNb target (Ru: 80 at%, Nb: 20 at%) is used, and a protective film made of RuNb is formed on the multilayer reflective film by DC magnetron sputtering in an Ar gas atmosphere. did. The thickness of the protective film was 2.5 nm.
　保護膜の上に、ＦＩＢ法によって、基準マークを形成した。
　ＦＩＢの条件は、以下の通りであった。
　　加速電圧：５０ｋＶ
　　ビーム電流値：２０ｐＡ A fiducial mark was formed on the protective film by FIB.
The conditions of FIB were as follows.
Acceleration voltage: 50kV
Beam current value: 20 pA
　基準マークの形状及び寸法は、以下の通りであった。
　　形状：略十字型
　　深さＤ：４０ｎｍ
　　幅Ｗ：２μｍ
　　長さＬ：１ｍｍ
　　傾斜角θ：８６度 The shape and dimensions of the fiducial marks were as follows.
Shape: approximately cruciform depth D: 40 nm
Width W: 2 μm
Length L: 1 mm
Inclination angle θ: 86 degrees
　基準マークの表層を、ＥＤＸ（エネルギー分散型Ｘ線分析）によって分析した。その結果、基準マークの表層には、保護膜に含まれている元素と同一の元素である、Ｒｕ及びＮｂが含まれておらず、Ｍｏ、及びＳｉが検出された。基準マークの表層には、保護膜が残存していないため、多層反射膜の材料が露出していたと考えられる。 The surface of the fiducial marks was analyzed by EDX (energy dispersive x-ray analysis). As a result, the surface layer of the reference mark did not contain Ru and Nb, which are the same elements as the elements contained in the protective film, and Mo and Si were detected. Since no protective film remains on the surface layer of the reference mark, it is considered that the material of the multilayer reflective film was exposed.
　欠陥検査装置（レーザーテック株式会社製、ABI）を用いて、多層反射膜付き基板の欠陥検査を行った。欠陥検査では、保護膜の上に凹状に形成された基準マークを基準として、欠陥の位置を特定した。その結果、欠陥の個数は、実施例１～３よりも大幅に増加していた。基準マークをＦＩＢによって加工した際に発生した塵によって、多層反射膜の表面が汚染されたことが原因であると推察される。また、基準マークを加工する時間が実施例１～３よりも大幅に増加した。 Defect inspection of the multilayer reflective film coated substrate was performed using a defect inspection apparatus (ABI manufactured by Lasertec Corporation). In defect inspection, the position of a defect was specified on the basis of a fiducial mark formed concavely on the protective film. As a result, the number of defects was significantly increased as compared with Examples 1 to 3. It is presumed that the surface of the multilayer reflective film is contaminated by dust generated when the fiducial mark is processed by FIB. In addition, the time to process the fiducial marks was significantly increased as compared with Examples 1 to 3.
　多層反射膜付き基板の保護膜の上に吸収体膜を形成し、反射型マスクブランクを製造した。具体的には、ＴａＢＮ（厚み５６ｎｍ）とＴａＢＯ（厚み１４ｎｍ）の積層膜からなる吸収体膜を、ＤＣマグネトロンスパッタリングにより形成した。ＴａＢＮ膜は、ＴａＢターゲットを使用し、ＡｒガスとＮ２ガスの混合ガス雰囲気における反応性スパッタリングにより形成した。ＴａＢＯ膜は、ＴａＢターゲットを使用し、ＡｒガスとＯ２ガスの混合ガス雰囲気における反応性スパッタリングにより形成した。 An absorber film was formed on the protective film of the multilayer reflective film coated substrate to manufacture a reflective mask blank. Specifically, an absorber film made of a laminated film of TaBN (56 nm in thickness) and TaBO (14 nm in thickness) was formed by DC magnetron sputtering. The TaBN film was formed by reactive sputtering in a mixed gas atmosphere of Ar gas and N 2 gas using a TaB target. The TaBO film was formed by reactive sputtering in a mixed gas atmosphere of Ar gas and O 2 gas using a TaB target.
　欠陥検査装置（レーザーテック株式会社製、M8350）を用いて、吸収体膜上の欠陥検査を行った。欠陥検査では、吸収体膜の上に凹状に転写された基準マークを基準として、欠陥の位置を特定した。その結果、欠陥の個数は、実施例１～３よりも大幅に増加していた。 Defect inspection on the absorber film was performed using a defect inspection apparatus (M8350 manufactured by Lasertec Corporation). In the defect inspection, the position of the defect was specified on the basis of the fiducial mark transferred concavely on the absorber film. As a result, the number of defects was significantly increased as compared with Examples 1 to 3.
　上記で製造した反射型マスクブランクの吸収体膜上に、レジスト膜を形成した。電子線描画装置を用いて、欠陥検査によって得られた欠陥情報に基づいてレジスト膜にパターンを描画した。パターンを描画した後、所定の現像処理を行い、吸収体膜上にレジストパターンを形成した。 A resist film was formed on the absorber film of the reflective mask blank manufactured above. A pattern was drawn on a resist film based on defect information obtained by defect inspection using an electron beam drawing apparatus. After drawing the pattern, predetermined development processing was performed to form a resist pattern on the absorber film.
　レジストパターンをマスクとして、吸収体膜にパターンを形成した。具体的には、フッ素系ガス（ＣＦ４ガス）により、上層のＴａＢＯ膜をドライエッチングした後、塩素系ガス（Ｃｌ２ガス）により、下層のＴａＢＮ膜をドライエッチングした。 Using the resist pattern as a mask, a pattern was formed on the absorber film. Specifically, the upper TaBO film was dry etched with a fluorine-based gas (CF 4 gas), and then the lower TaBN film was dry etched with a chlorine-based gas (Cl 2 gas).
　吸収体膜パターン上に残ったレジストパターンを、熱硫酸で除去することで、比較例１に係る反射型マスクが得られた。こうして得られた反射型マスクを露光装置にセットし、レジスト膜を形成した半導体基板上へのパターン転写を行う場合、反射型マスク起因の転写パターンの欠陥が実施例１～３よりも多くなるため、良好なパターン転写を行うことが困難である。 By removing the resist pattern remaining on the absorber film pattern with hot sulfuric acid, a reflective mask according to Comparative Example 1 was obtained. When the thus obtained reflective mask is set in an exposure apparatus and pattern transfer is performed on a semiconductor substrate on which a resist film is formed, the number of defects in the transfer pattern caused by the reflective mask is greater than in the first to third embodiments. It is difficult to perform good pattern transfer.
１０　　多層反射膜付き基板
１２　　基板
１４　　多層反射膜
１８　　保護膜
２０　　基準マーク
２４　　シュリンク領域
２６　　ミキシング領域
２８　　吸収体膜
３０　　反射型マスクブランク
３２　　レジスト膜
４０　　反射型マスク
５０　　パターン転写装置 DESCRIPTION OF SYMBOLS 10 multi-layer reflective film coated substrate 12 substrate 14 multi-layer reflective film 18 protective film 20 reference mark 24 shrink area 26 mixing area 28 absorber film 30 reflective mask blank 32 resist film 40 reflective mask 50 pattern transfer device

Claims (9)

  1. 　基板と、前記基板上に形成されたＥＵＶ光を反射する多層反射膜と、前記多層反射膜上に形成された保護膜とを含む多層反射膜付き基板であって、
    　前記保護膜の表面に凹状に形成された基準マークを備え、
    　前記基準マークの表層は、前記保護膜に含まれる元素のうち少なくとも１つの元素と同一の元素を含み、
    　前記基準マークの底部において、前記多層反射膜に含まれる複数の膜のうち少なくとも一部の膜が収縮したシュリンク領域を有することを特徴とする、多層反射膜付き基板。     A multilayer reflective film coated substrate comprising: a substrate; a multilayer reflective film for reflecting EUV light formed on the substrate; and a protective film formed on the multilayer reflective film,
    It has a fiducial mark formed concavely on the surface of the protective film,
    The surface layer of the reference mark contains an element identical to at least one of the elements contained in the protective film,
    A multilayer reflective film coated substrate having a shrink region in which at least a part of a plurality of films included in the multilayer reflective film is contracted at the bottom of the reference mark.
  2. 　前記基準マークの表層は、Ｒｕを含む、請求項１に記載の多層反射膜付き基板。 The multilayer reflective film coated substrate according to claim 1, wherein the surface layer of the reference mark includes Ru.
  3. 　前記基準マークの表層は、ＲｕＯ、ＲｕＮｂＯ、ＲｕＳｉ、及びＲｕＳｉＯ からなる群から選ばれる少なくとも１つを含む、請求項２に記載の多層反射膜付き基板。 The multilayer reflective film coated substrate according to claim 2, wherein the surface layer of the reference mark includes at least one selected from the group consisting of RuO, RuNbO, RuSi, and RuSiO 2.
  4. 　前記基準マークの底部において、前記多層反射膜に含まれる複数の膜のうち少なくとも一部の膜が互いに一体化したミキシング領域を有する、請求項１から請求項３のうちいずれか１項に記載の多層反射膜付き基板。 The mixing region according to any one of claims 1 to 3, wherein at the bottom of the reference mark, at least a part of the plurality of films included in the multilayer reflective film has a mixing area integrated with each other. Multilayer reflective film coated substrate.
  5. 　前記基準マークの深さが３０ｎｍ以上５０ｎｍ以下である、請求項１から請求項４のうちいずれか１項に記載の多層反射膜付き基板。 The multilayer reflective film coated substrate according to any one of claims 1 to 4, wherein the depth of the reference mark is 30 nm or more and 50 nm or less.
  6. 　前記多層反射膜の前記基板と反対側の表面層はＳｉを含む層である、請求項１から請求項５のうちいずれか１項に記載の多層反射膜付き基板。 The multilayer reflective film coated substrate according to any one of claims 1 to 5, wherein the surface layer opposite to the substrate of the multilayer reflective film is a layer containing Si.
  7. 　請求項１から請求項６のうちいずれか１項に記載の多層反射膜付き基板と、当該多層反射膜付き基板の保護膜上に形成された、ＥＵＶ光を吸収する吸収体膜とを有する反射型マスクブランクであって、
    　前記吸収体膜に前記基準マークの形状が転写されている、反射型マスクブランク。     A reflection having a multilayer reflective film coated substrate according to any one of claims 1 to 6 and an absorber film which is formed on a protective film of the multilayer reflective film coated substrate and which absorbs EUV light. Type mask blank,
    A reflective mask blank, wherein the shape of the reference mark is transferred to the absorber film.
  8. 　請求項１から請求項６のうちいずれか１項に記載の多層反射膜付き基板と、当該多層反射膜付き基板の保護膜上に形成された、ＥＵＶ光を吸収する吸収体膜パターンとを有する反射型マスクであって、
    　前記吸収体膜パターンに前記基準マークの形状が転写されている、反射型マスク。     A multilayer reflective film coated substrate according to any one of claims 1 to 6, and an absorber film pattern formed on the protective film of the multilayer reflective film coated substrate for absorbing EUV light. A reflective mask,
    A reflective mask, wherein the shape of the reference mark is transferred to the absorber film pattern.
  9. 　請求項８に記載の反射型マスクを使用して、半導体基板上に転写パターンを形成する工程を有する、半導体装置の製造方法。 A method of manufacturing a semiconductor device, comprising the step of forming a transfer pattern on a semiconductor substrate using the reflective mask according to claim 8.
PCT/JP2018/038499 2017-10-17 2018-10-16 Substrate equipped with multi-layer reflection film, reflection-type mask blank, reflection-type mask, and semiconductor device manufacturing process WO2019078205A1 (en)

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